Pub Date : 2024-08-15DOI: 10.1021/acs.biochem.4c0030810.1021/acs.biochem.4c00308
Saskia Hutten*, Jia-Xuan Chen, Adrian M. Isaacs and Dorothee Dormann*,
Dipeptide repeat proteins (DPRs) are aberrant protein species found in C9orf72-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two neurodegenerative diseases characterized by the cytoplasmic mislocalization and aggregation of RNA-binding proteins (RBPs). In particular, arginine (R)-rich DPRs (poly-GR and poly-PR) have been suggested to promiscuously interact with multiple cellular proteins and thereby exert high cytotoxicity. Components of the protein arginine methylation machinery have been identified as modulators of DPR toxicity and/or potential cellular interactors of R-rich DPRs; however, the molecular details and consequences of such an interaction are currently not well understood. Here, we demonstrate that several members of the family of protein arginine methyltransferases (PRMTs) can directly interact with R-rich DPRs in vitro and in the cytosol. In vitro, R-rich DPRs reduce solubility and promote phase separation of PRMT1, the main enzyme responsible for asymmetric arginine-dimethylation (ADMA) in mammalian cells, in a concentration- and length-dependent manner. Moreover, we demonstrate that poly-GR interferes more efficiently than poly-PR with PRMT1-mediated arginine methylation of RBPs such as hnRNPA3. We additionally show by two alternative approaches that poly-GR itself is a substrate for PRMT1-mediated arginine dimethylation. We propose that poly-GR may act as a direct competitor for arginine methylation of cellular PRMT1 targets, such as disease-linked RBPs.
{"title":"Poly-GR Impairs PRMT1-Mediated Arginine Methylation of Disease-Linked RNA-Binding Proteins by Acting as a Substrate Sink","authors":"Saskia Hutten*, Jia-Xuan Chen, Adrian M. Isaacs and Dorothee Dormann*, ","doi":"10.1021/acs.biochem.4c0030810.1021/acs.biochem.4c00308","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00308https://doi.org/10.1021/acs.biochem.4c00308","url":null,"abstract":"<p >Dipeptide repeat proteins (DPRs) are aberrant protein species found in C9orf72-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two neurodegenerative diseases characterized by the cytoplasmic mislocalization and aggregation of RNA-binding proteins (RBPs). In particular, arginine (R)-rich DPRs (poly-GR and poly-PR) have been suggested to promiscuously interact with multiple cellular proteins and thereby exert high cytotoxicity. Components of the protein arginine methylation machinery have been identified as modulators of DPR toxicity and/or potential cellular interactors of R-rich DPRs; however, the molecular details and consequences of such an interaction are currently not well understood. Here, we demonstrate that several members of the family of protein arginine methyltransferases (PRMTs) can directly interact with R-rich DPRs in vitro and in the cytosol. In vitro, R-rich DPRs reduce solubility and promote phase separation of PRMT1, the main enzyme responsible for asymmetric arginine-dimethylation (ADMA) in mammalian cells, in a concentration- and length-dependent manner. Moreover, we demonstrate that poly-GR interferes more efficiently than poly-PR with PRMT1-mediated arginine methylation of RBPs such as hnRNPA3. We additionally show by two alternative approaches that poly-GR itself is a substrate for PRMT1-mediated arginine dimethylation. We propose that poly-GR may act as a direct competitor for arginine methylation of cellular PRMT1 targets, such as disease-linked RBPs.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142135436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-14DOI: 10.1021/acs.biochem.4c0042610.1021/acs.biochem.4c00426
Alex Kentsis, and , Tobin R. Sosnick*,
{"title":"Correction to “Trifluoroethanol Promotes Helix Formation by Destabilizing Backbone Exposure: Desolvation Rather than Native Hydrogen Bonding Defines the Kinetic Pathway of Dimeric Coiled Coil Folding”","authors":"Alex Kentsis, and , Tobin R. Sosnick*, ","doi":"10.1021/acs.biochem.4c0042610.1021/acs.biochem.4c00426","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00426https://doi.org/10.1021/acs.biochem.4c00426","url":null,"abstract":"","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142135423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-14DOI: 10.1021/acs.biochem.4c0033010.1021/acs.biochem.4c00330
Danna Dong, Mingyu Xia, Sili Wang*, Pengfei Fang* and Wen Liu*,
Mitomycins make up a class of natural molecules produced by Streptomyces with strong antibacterial and antitumor activities. MitM is a key postmitosane modification enzyme involved in mitomycin biosynthesis in Streptomyces caespitosus. This protein was previously suggested to catalyze the aziridinium methylation of mitomycin A and the mitomycin intermediate 9a-demethyl-mitomycin A as an N-methyltransferase. The structural basis for MitM to recognize cofactor S-adenosyl-l-methionine (SAM) and substrate mitomycin A is unknown. Here, we determined the crystal structures of apo-MitM and MitM-mitomycin A-S-adenosylhomocysteine (SAH) ternary complexes with resolutions of 2.23 and 2.80 Å, respectively. We found that MitM adopts a class I SAM-dependent methyltransferase fold and forms a homodimer in solution. Conformational changes in a series of residues involved in the formation of active pockets assist MitM in binding SAH and mitomycin A. In particular, the 28ALGAASLGE36 loop changes most significantly. When mitomycin A binds, the bending direction of this loop is reversed, changing the entrance of the active site from open to closed. This study provides structural insights into MitM’s involvement in the postmitosane stage of mitomycin biosynthesis and provides a template for the engineering of methyltransferases.
丝裂霉素是由链霉菌产生的一类天然分子,具有很强的抗菌和抗肿瘤活性。MitM 是一种参与丝裂霉素生物合成的关键后mitosane修饰酶。此前曾有研究认为,该蛋白作为一种 N-甲基转移酶,可催化丝裂霉素 A 和丝裂霉素中间体 9a-demethyl-mitomycin A 的氮丙啶甲基化。MitM 识别辅助因子 S-腺苷-l-蛋氨酸(SAM)和底物丝裂霉素 A 的结构基础尚不清楚。在这里,我们测定了 apo-MitM 和 MitM-mitomycin A-S-adenosylhomocysteine (SAH) 三元复合物的晶体结构,分辨率分别为 2.23 和 2.80 Å。我们发现 MitM 采用一类 SAM 依赖性甲基转移酶折叠,并在溶液中形成同源二聚体。一系列参与形成活性口袋的残基发生了构象变化,这有助于 MitM 与 SAH 和丝裂霉素 A 结合。当丝裂霉素 A 结合时,该环路的弯曲方向发生逆转,使活性位点的入口从开放变为封闭。这项研究从结构上揭示了 MitM 参与丝裂霉素生物合成的后mitosane 阶段,并为甲基转移酶的工程设计提供了模板。
{"title":"Structural Basis of Substrate Recognition by the Postmitosane Modification Enzyme MitM in Mitomycin Biosynthesis","authors":"Danna Dong, Mingyu Xia, Sili Wang*, Pengfei Fang* and Wen Liu*, ","doi":"10.1021/acs.biochem.4c0033010.1021/acs.biochem.4c00330","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00330https://doi.org/10.1021/acs.biochem.4c00330","url":null,"abstract":"<p >Mitomycins make up a class of natural molecules produced by <i>Streptomyces</i> with strong antibacterial and antitumor activities. MitM is a key postmitosane modification enzyme involved in mitomycin biosynthesis in <i>Streptomyces caespitosus</i>. This protein was previously suggested to catalyze the aziridinium methylation of mitomycin A and the mitomycin intermediate 9a-demethyl-mitomycin A as an <i>N</i>-methyltransferase. The structural basis for MitM to recognize cofactor <i>S</i>-adenosyl-<span>l</span>-methionine (SAM) and substrate mitomycin A is unknown. Here, we determined the crystal structures of <i>apo</i>-MitM and MitM-mitomycin A-<i>S</i>-adenosylhomocysteine (SAH) ternary complexes with resolutions of 2.23 and 2.80 Å, respectively. We found that MitM adopts a class I SAM-dependent methyltransferase fold and forms a homodimer in solution. Conformational changes in a series of residues involved in the formation of active pockets assist MitM in binding SAH and mitomycin A. In particular, the <sub>28</sub>ALGAASLGE<sub>36</sub> loop changes most significantly. When mitomycin A binds, the bending direction of this loop is reversed, changing the entrance of the active site from open to closed. This study provides structural insights into MitM’s involvement in the postmitosane stage of mitomycin biosynthesis and provides a template for the engineering of methyltransferases.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142135424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-14DOI: 10.1021/acs.biochem.4c0008510.1021/acs.biochem.4c00085
Mayuka Nii, Kohei Yamaguchi, Toshifumi Tojo, Nozomi Narushima and Shin Aoki*,
In previous work, we reported on iridium(III) (Ir(III)) complex-peptide hybrids as amphiphilic conjugates (IPH-ACs) and triptycene-peptide hybrids as amphiphilic conjugates (TPH-ACs) and found that these hybrid compounds containing three cationic KK(K)GG peptide units through C6–C8 alkyl linkers induce paraptosis II, which is one of the nonapoptotic programmed cell death (PCD) types in Jurkat cells and different from previously reported paraptosis. The details of that study revealed that the paraptosis II induced by IPH-ACs (and TPH-ACs) proceeds via a membrane fusion or tethering of the endoplasmic reticulum (ER) and mitochondria, and Ca2+ transfer from the ER to mitochondria, which results in a loss of mitochondrial membrane potential (ΔΨm) in Jurkat cells. However, the detailed mechanistic studies of paraptosis II have been conducted only in Jurkat cells. In the present work, we decided to conduct mechanistic studies of paraptosis II in HeLa-S3 and A549 cells as well as in Jurkat cells to study the general mechanism of paraptosis II. Simultaneously, we designed and synthesized new TPH-ACs functionalized with peptides that contain cyclohexylalanine, which had been reported to enhance the localization of peptides to mitochondria. We found that TPH-ACs containing cyclohexylalanine promote paraptosis II processes in Jurkat, HeLa-S3 and A549 cells. The results of the experiments using fluorescence Ca2+ probes in mitochondria and cytosol, fluorescence staining agents of mitochondria and the ER, and inhibitors of paraptosis II suggest that TPH-ACs induce Ca2+ increase in mitochondria and the membrane fusion between the ER and mitochondria almost simultaneously, suggesting that our previous hypothesis on the mechanism of paraptosis II should be revised.
在之前的工作中,我们报道了铱(III)(Ir(III))络合物-肽杂化物两亲共轭物(IPH-ACs)和三庚烯-肽杂化物两亲共轭物(TPH-ACs),并发现这些杂化物通过C6-C8烷基连接体含有三个阳离子KK(K)GG肽单元,可诱导跃层沉着II、这是 Jurkat 细胞的非凋亡程序性细胞死亡(PCD)类型之一,与之前报道的凋亡不同。该研究的详细结果表明,IPH-AC(和 TPH-AC)诱导的副凋亡 II 是通过内质网(ER)和线粒体的膜融合或拴系,以及从 ER 到线粒体的 Ca2+ 转移进行的,这导致了 Jurkat 细胞中线粒体膜电位(ΔΨm)的丧失。然而,关于副aptosis II 的详细机理研究只在 Jurkat 细胞中进行过。在本研究中,我们决定在 HeLa-S3 和 A549 细胞以及 Jurkat 细胞中进行跃变 II 的机理研究,以研究跃变 II 的一般机理。同时,我们设计并合成了含有环己基丙氨酸的肽功能化的新型 TPH-ACs ,有报道称环己基丙氨酸能增强肽在线粒体中的定位。我们发现,含有环己基丙氨酸的 TPH-ACs 能促进 Jurkat、HeLa-S3 和 A549 细胞中的跃迁 II 过程。使用线粒体和细胞质中的荧光 Ca2+ 探针、线粒体和 ER 的荧光染色剂以及副aptosis II 抑制剂进行的实验结果表明,TPH-ACs 几乎同时诱导线粒体中 Ca2+ 的增加以及 ER 和线粒体之间的膜融合,这表明我们之前关于副aptosis II 机制的假设应予以修正。
{"title":"Induction of Paraptotic Cell Death in Cancer Cells by Triptycene–Peptide Hybrids and the Revised Mechanism of Paraptosis II","authors":"Mayuka Nii, Kohei Yamaguchi, Toshifumi Tojo, Nozomi Narushima and Shin Aoki*, ","doi":"10.1021/acs.biochem.4c0008510.1021/acs.biochem.4c00085","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00085https://doi.org/10.1021/acs.biochem.4c00085","url":null,"abstract":"<p >In previous work, we reported on iridium(III) (Ir(III)) complex-peptide hybrids as amphiphilic conjugates (IPH-ACs) and triptycene-peptide hybrids as amphiphilic conjugates (TPH-ACs) and found that these hybrid compounds containing three cationic KK(K)GG peptide units through C<sub>6</sub>–C<sub>8</sub> alkyl linkers induce paraptosis II, which is one of the nonapoptotic programmed cell death (PCD) types in Jurkat cells and different from previously reported paraptosis. The details of that study revealed that the paraptosis II induced by IPH-ACs (and TPH-ACs) proceeds via a membrane fusion or tethering of the endoplasmic reticulum (ER) and mitochondria, and Ca<sup>2+</sup> transfer from the ER to mitochondria, which results in a loss of mitochondrial membrane potential (<i>ΔΨ</i><sub>m</sub>) in Jurkat cells. However, the detailed mechanistic studies of paraptosis II have been conducted only in Jurkat cells. In the present work, we decided to conduct mechanistic studies of paraptosis II in HeLa-S3 and A549 cells as well as in Jurkat cells to study the general mechanism of paraptosis II. Simultaneously, we designed and synthesized new TPH-ACs functionalized with peptides that contain cyclohexylalanine, which had been reported to enhance the localization of peptides to mitochondria. We found that TPH-ACs containing cyclohexylalanine promote paraptosis II processes in Jurkat, HeLa-S3 and A549 cells. The results of the experiments using fluorescence Ca<sup>2+</sup> probes in mitochondria and cytosol, fluorescence staining agents of mitochondria and the ER, and inhibitors of paraptosis II suggest that TPH-ACs induce Ca<sup>2+</sup> increase in mitochondria and the membrane fusion between the ER and mitochondria almost simultaneously, suggesting that our previous hypothesis on the mechanism of paraptosis II should be revised.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.biochem.4c00085","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142135426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-13DOI: 10.1021/acs.biochem.4c0024310.1021/acs.biochem.4c00243
Harrison C. Greenberg, Ananya Majumdar, Ekroop Kaur Cheema, Anton Kozyryev and Steven E. Rokita*,
Active site lids are common features of enzymes and typically undergo conformational changes upon substrate binding to promote catalysis. Iodotyrosine deiodinase is no exception and contains a lid segment in all of its homologues from human to bacteria. The solution-state dynamics of the lid have now been characterized using 19F NMR spectroscopy with a CF3-labeled enzyme and CF3O-labeled ligands. From two-dimensional 19F–19F NMR exchange spectroscopy, interconversion rates between the free and bound states of a CF3O-substituted tyrosine (45 ± 10 s–1) and the protein label (40 ± 3 s–1) are very similar and suggest a correlation between ligand binding and conformational reorganization of the lid. Both occur at rates that are ∼100-fold faster than turnover, and therefore these steps do not limit catalysis. A simple CF3O-labeled phenol also binds to the active site and induces a conformational change in the lid segment that was not previously detectable by crystallography. Exchange rates of the ligand (130 ± 20 s–1) and protein (98 ± 8 s–1) in this example are faster than those above but remain self-consistent to affirm a correlation between ordering of the lid and binding of the ligand. Both ligands also protect the protein from limited proteolysis, as expected from their ability to stabilize a compact lid structure. However, the minimal turnover of simple phenol substrates indicates that such stabilization may be necessary but is not sufficient for efficient catalysis.
{"title":"19F NMR Reveals the Dynamics of Substrate Binding and Lid Closure for Iodotyrosine Deiodinase as a Complement to Steady-State Kinetics and Crystallography","authors":"Harrison C. Greenberg, Ananya Majumdar, Ekroop Kaur Cheema, Anton Kozyryev and Steven E. Rokita*, ","doi":"10.1021/acs.biochem.4c0024310.1021/acs.biochem.4c00243","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00243https://doi.org/10.1021/acs.biochem.4c00243","url":null,"abstract":"<p >Active site lids are common features of enzymes and typically undergo conformational changes upon substrate binding to promote catalysis. Iodotyrosine deiodinase is no exception and contains a lid segment in all of its homologues from human to bacteria. The solution-state dynamics of the lid have now been characterized using <sup>19</sup>F NMR spectroscopy with a CF<sub>3</sub>-labeled enzyme and CF<sub>3</sub>O-labeled ligands. From two-dimensional <sup>19</sup>F–<sup>19</sup>F NMR exchange spectroscopy, interconversion rates between the free and bound states of a CF<sub>3</sub>O-substituted tyrosine (45 ± 10 s<sup>–1</sup>) and the protein label (40 ± 3 s<sup>–1</sup>) are very similar and suggest a correlation between ligand binding and conformational reorganization of the lid. Both occur at rates that are ∼100-fold faster than turnover, and therefore these steps do not limit catalysis. A simple CF<sub>3</sub>O-labeled phenol also binds to the active site and induces a conformational change in the lid segment that was not previously detectable by crystallography. Exchange rates of the ligand (130 ± 20 s<sup>–1</sup>) and protein (98 ± 8 s<sup>–1</sup>) in this example are faster than those above but remain self-consistent to affirm a correlation between ordering of the lid and binding of the ligand. Both ligands also protect the protein from limited proteolysis, as expected from their ability to stabilize a compact lid structure. However, the minimal turnover of simple phenol substrates indicates that such stabilization may be necessary but is not sufficient for efficient catalysis.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142135291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-13DOI: 10.1021/acs.biochem.4c0033110.1021/acs.biochem.4c00331
Lanette LaComb, Agnidipta Ghosh*, Jeffrey B. Bonanno, Daniel J. Nilson, Alex J. Poppel, Lucas Dada, Sean M. Cahill, Juan Pablo Maianti, Seiya Kitamura, David Cowburn* and Steven C. Almo*,
The Enabled/VASP homology 1 (EVH1) domain is a small module that interacts with proline-rich stretches in its ligands and is found in various signaling and scaffolding proteins. Mena, the mammalian homologue of Ena, is involved in diverse actin-associated events, such as membrane dynamics, bacterial motility, and tumor intravasation and extravasation. Two-dimensional (2D) 1H–15N HSQC NMR was used to study Mena EVH1 binding properties, defining the amino acids involved in ligand recognition for the physiological ligands ActA and PCARE, and a synthetic polyproline-inspired small molecule (hereafter inhibitor 6c). Chemical shift perturbations indicated that proline-rich segments bind in the conserved EVH1 hydrophobic cleft. The PCARE-derived peptide elicited more perturbations compared to the ActA-derived peptide, consistent with a previous report of a structural alteration in the solvent-exposed β7-β8 loop. Unexpectedly, EVH1 and the proline-rich segment of PTP1B did not exhibit NMR chemical shift perturbations; however, the high-resolution crystal structure implicated the conserved EVH1 hydrophobic cleft in ligand recognition. Intrinsic steady-state fluorescence and fluorescence polarization assays indicate that residues outside the proline-rich segment enhance the ligand affinity for EVH1 (Kd = 3–8 μM). Inhibitor 6c displayed tighter binding (Kd ∼ 0.3 μM) and occupies the same EVH1 cleft as physiological ligands. These studies revealed that the EVH1 domain enhances ligand affinity through recognition of residues flanking the proline-rich segments. Additionally, a synthetic inhibitor binds more tightly to the EVH1 domain than natural ligands, occupying the same hydrophobic cleft.
{"title":"Insights into the Interaction Landscape of the EVH1 Domain of Mena","authors":"Lanette LaComb, Agnidipta Ghosh*, Jeffrey B. Bonanno, Daniel J. Nilson, Alex J. Poppel, Lucas Dada, Sean M. Cahill, Juan Pablo Maianti, Seiya Kitamura, David Cowburn* and Steven C. Almo*, ","doi":"10.1021/acs.biochem.4c0033110.1021/acs.biochem.4c00331","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00331https://doi.org/10.1021/acs.biochem.4c00331","url":null,"abstract":"<p >The Enabled/VASP homology 1 (EVH1) domain is a small module that interacts with proline-rich stretches in its ligands and is found in various signaling and scaffolding proteins. Mena, the mammalian homologue of Ena, is involved in diverse actin-associated events, such as membrane dynamics, bacterial motility, and tumor intravasation and extravasation. Two-dimensional (2D) <sup>1</sup>H–<sup>15</sup>N HSQC NMR was used to study Mena EVH1 binding properties, defining the amino acids involved in ligand recognition for the physiological ligands ActA and PCARE, and a synthetic polyproline-inspired small molecule (hereafter inhibitor <b>6c</b>). Chemical shift perturbations indicated that proline-rich segments bind in the conserved EVH1 hydrophobic cleft. The PCARE-derived peptide elicited more perturbations compared to the ActA-derived peptide, consistent with a previous report of a structural alteration in the solvent-exposed β7-β8 loop. Unexpectedly, EVH1 and the proline-rich segment of PTP1B did not exhibit NMR chemical shift perturbations; however, the high-resolution crystal structure implicated the conserved EVH1 hydrophobic cleft in ligand recognition. Intrinsic steady-state fluorescence and fluorescence polarization assays indicate that residues outside the proline-rich segment enhance the ligand affinity for EVH1 (<i>K</i><sub>d</sub> = 3–8 μM). Inhibitor <b>6c</b> displayed tighter binding (<i>K</i><sub>d</sub> ∼ 0.3 μM) and occupies the same EVH1 cleft as physiological ligands. These studies revealed that the EVH1 domain enhances ligand affinity through recognition of residues flanking the proline-rich segments. Additionally, a synthetic inhibitor binds more tightly to the EVH1 domain than natural ligands, occupying the same hydrophobic cleft.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142135292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-12DOI: 10.1021/acs.biochem.4c0017210.1021/acs.biochem.4c00172
Priya Rana, Rajat Ujjainiya, Vishal Bharti, Souvik Maiti and Mary K. Ekka*,
The intricate regulation of gene expression is fundamental to the biological complexity of higher organisms, and is primarily governed by transcriptional and post-transcriptional mechanisms. The 3′-untranslated region (3′UTR) of mRNA is rich in cis-regulatory elements like G-quadruplexes (G4s), and plays a crucial role in post-transcriptional regulation. G4s have emerged as significant gene regulators, impacting mRNA stability, translation, and localization. In this study, we investigate the role of a robust parallel G4 structure situated within the 3′UTR of CCN1 mRNA in post-transcriptional regulation. This G4 structure is proximal to the stop codon of human CCN1, and evolutionarily conserved. We elucidated its interaction with the insulin-like growth factor 2 binding protein 1 (IGF2BP1), a noncanonical RNA N6-methyladenosine (m6A) modification reader, revealing a novel interplay between RNA modifications and G-quadruplex structures. Knockdown experiments and mutagenesis studies demonstrate that IGF2BP1 binds specifically to the G4 structure, modulating CCN1 mRNA stability. Additionally, we unveil the role of IGF2BP1’s RNA recognition motifs in G4 recognition, highlighting this enthalpically driven interaction. Our findings offer fresh perspectives on the complex mechanisms of post-transcriptional gene regulation mediated by G4 RNA secondary structures.
{"title":"IGF2BP1-Mediated Regulation of CCN1 Expression by Specific Binding to G-Quadruplex Structure in Its 3′UTR","authors":"Priya Rana, Rajat Ujjainiya, Vishal Bharti, Souvik Maiti and Mary K. Ekka*, ","doi":"10.1021/acs.biochem.4c0017210.1021/acs.biochem.4c00172","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00172https://doi.org/10.1021/acs.biochem.4c00172","url":null,"abstract":"<p >The intricate regulation of gene expression is fundamental to the biological complexity of higher organisms, and is primarily governed by transcriptional and post-transcriptional mechanisms. The 3′-untranslated region (3′UTR) of mRNA is rich in cis-regulatory elements like G-quadruplexes (G4s), and plays a crucial role in post-transcriptional regulation. G4s have emerged as significant gene regulators, impacting mRNA stability, translation, and localization. In this study, we investigate the role of a robust parallel G4 structure situated within the 3′UTR of CCN1 mRNA in post-transcriptional regulation. This G4 structure is proximal to the stop codon of human CCN1, and evolutionarily conserved. We elucidated its interaction with the insulin-like growth factor 2 binding protein 1 (IGF2BP1), a noncanonical RNA N6-methyladenosine (m6A) modification reader, revealing a novel interplay between RNA modifications and G-quadruplex structures. Knockdown experiments and mutagenesis studies demonstrate that IGF2BP1 binds specifically to the G4 structure, modulating CCN1 mRNA stability. Additionally, we unveil the role of IGF2BP1’s RNA recognition motifs in G4 recognition, highlighting this enthalpically driven interaction. Our findings offer fresh perspectives on the complex mechanisms of post-transcriptional gene regulation mediated by G4 RNA secondary structures.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142135181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-12DOI: 10.1021/acs.biochem.4c0032010.1021/acs.biochem.4c00320
Gwen Tjallinks, Andrea Mattevi and Marco W. Fraaije*,
Berberine bridge enzyme-like oxidases are often involved in natural product biosynthesis and are seen as essential enzymes for the generation of intricate pharmacophores. These oxidases have the ability to transfer a hydride atom to the FAD cofactor, which enables complex substrate modifications and rearrangements including (intramolecular) cyclizations, carbon–carbon bond formations, and nucleophilic additions. Despite the diverse range of activities, the mechanistic details of these reactions often remain incompletely understood. In this Review, we delve into the complexity that BBE-like oxidases from bacteria, fungal, and plant origins exhibit by providing an overview of the shared catalytic features and emphasizing the different reactivities. We propose four generalized modes of action by which BBE-like oxidases enable the synthesis of natural products, ranging from the classic alcohol oxidation reactions to less common amine and amide oxidation reactions. Exploring the mechanisms utilized by nature to produce its vast array of natural products is a subject of considerable interest and can lead to the discovery of unique biochemical activities.
{"title":"Biosynthetic Strategies of Berberine Bridge Enzyme-like Flavoprotein Oxidases toward Structural Diversification in Natural Product Biosynthesis","authors":"Gwen Tjallinks, Andrea Mattevi and Marco W. Fraaije*, ","doi":"10.1021/acs.biochem.4c0032010.1021/acs.biochem.4c00320","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00320https://doi.org/10.1021/acs.biochem.4c00320","url":null,"abstract":"<p >Berberine bridge enzyme-like oxidases are often involved in natural product biosynthesis and are seen as essential enzymes for the generation of intricate pharmacophores. These oxidases have the ability to transfer a hydride atom to the FAD cofactor, which enables complex substrate modifications and rearrangements including (intramolecular) cyclizations, carbon–carbon bond formations, and nucleophilic additions. Despite the diverse range of activities, the mechanistic details of these reactions often remain incompletely understood. In this Review, we delve into the complexity that BBE-like oxidases from bacteria, fungal, and plant origins exhibit by providing an overview of the shared catalytic features and emphasizing the different reactivities. We propose four generalized modes of action by which BBE-like oxidases enable the synthesis of natural products, ranging from the classic alcohol oxidation reactions to less common amine and amide oxidation reactions. Exploring the mechanisms utilized by nature to produce its vast array of natural products is a subject of considerable interest and can lead to the discovery of unique biochemical activities.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.biochem.4c00320","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142135180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1021/acs.biochem.4c0020410.1021/acs.biochem.4c00204
Elahe Lotfi Shahpar, Atiyeh Mahdavi* and Zahra Mohamadnia,
Melanin biosynthesis in different organisms is performed by a tyrosinase action. Excessive enzyme activity and pigment accumulation result in different diseases and disorders including skin cancers, blemishes, and darkening. In fruits and vegetables, it causes unwanted browning of these products and reduces their appearance quality and economic value. Inhibiting enzyme activity and finding novel powerful and safe inhibitors are highly important in agriculture, food, medical, and pharmaceutical industries. In this regard, in the present study, some novel synthetic pyridine-based compounds including 2,6-bis (tosyloxymethyl) pyridine (compound 3), 2,6-bis (butylthiomethyl) pyridine (compound 4), and 2,6-bis (phenylthiomethyl) pyridine (compound 5) were synthesized for the first time, and their inhibitory potencies were assessed on mushroom tyrosinase diphenolase activity. The results showed that while all tested compounds significantly decreased the enzyme activity, compounds 4 and 5 had the highest inhibitory effects (respectively, 80 and 89% inhibition with the IC50 values of 17.0 and 9.0 μmol L–1), and the inhibition mechanism was mixed-type for both compounds. Ligand-binding studies were carried out by fluorescence quenching and molecular docking methods to investigate the enzyme–compound interactions. Fluorescence quenching results revealed that the compounds can form nonfluorescent complexes with the enzyme and result in quenching of its intrinsic emission by the static process. Molecular docking analyses predicted the binding positions and the amino acid residues involved in the interactions. These compounds appear to be suitable candidates for more studies on tyrosinase inhibition.
{"title":"Inhibitory Effects, Fluorescence Studies, and Molecular Docking Analysis of Some Novel Pyridine-Based Compounds on Mushroom Tyrosinase","authors":"Elahe Lotfi Shahpar, Atiyeh Mahdavi* and Zahra Mohamadnia, ","doi":"10.1021/acs.biochem.4c0020410.1021/acs.biochem.4c00204","DOIUrl":"https://doi.org/10.1021/acs.biochem.4c00204https://doi.org/10.1021/acs.biochem.4c00204","url":null,"abstract":"<p >Melanin biosynthesis in different organisms is performed by a tyrosinase action. Excessive enzyme activity and pigment accumulation result in different diseases and disorders including skin cancers, blemishes, and darkening. In fruits and vegetables, it causes unwanted browning of these products and reduces their appearance quality and economic value. Inhibiting enzyme activity and finding novel powerful and safe inhibitors are highly important in agriculture, food, medical, and pharmaceutical industries. In this regard, in the present study, some novel synthetic pyridine-based compounds including 2,6-bis (tosyloxymethyl) pyridine (compound <b>3</b>), 2,6-bis (butylthiomethyl) pyridine (compound <b>4</b>), and 2,6-bis (phenylthiomethyl) pyridine (compound <b>5</b>) were synthesized for the first time, and their inhibitory potencies were assessed on mushroom tyrosinase diphenolase activity. The results showed that while all tested compounds significantly decreased the enzyme activity, compounds <b>4</b> and <b>5</b> had the highest inhibitory effects (respectively, 80 and 89% inhibition with the IC<sub>50</sub> values of 17.0 and 9.0 μmol L<sup>–1</sup>), and the inhibition mechanism was mixed-type for both compounds. Ligand-binding studies were carried out by fluorescence quenching and molecular docking methods to investigate the enzyme–compound interactions. Fluorescence quenching results revealed that the compounds can form nonfluorescent complexes with the enzyme and result in quenching of its intrinsic emission by the static process. Molecular docking analyses predicted the binding positions and the amino acid residues involved in the interactions. These compounds appear to be suitable candidates for more studies on tyrosinase inhibition.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142010819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06Epub Date: 2024-07-04DOI: 10.1021/acs.biochem.4c00076
Koteswara Rao Gorantla, Anandhu Krishnan, Sodiq O Waheed, Ann Varghese, Isabella DiCastri, Ciara LaRouche, Meredith Paik, Gregg B Fields, Tatyana G Karabencheva-Christova
Collagen hydrolysis, catalyzed by Zn(II)-dependent matrix metalloproteinases (MMPs), is a critical physiological process. Despite previous computational investigations into the catalytic mechanisms of MMP-mediated collagenolysis, a significant knowledge gap in understanding remains regarding the influence of conformational sampling and entropic contributions at physiological temperature on enzymatic collagenolysis. In our comprehensive multilevel computational study, employing quantum mechanics/molecular mechanics (QM/MM) metadynamics (MetD) simulations, we aimed to bridge this gap and provide valuable insights into the catalytic mechanism of MMP-1. Specifically, we compared the full enzyme-substrate complex in solution, clusters in solution, and gas-phase to elucidate insights into MMP-1-catalyzed collagenolysis. Our findings reveal significant differences in the catalytic mechanism when considering thermal effects and the dynamic evolution of the system, contrasting with conventional static potential energy surface QM/MM reaction path studies. Notably, we observed a significant stabilization of the critical tetrahedral intermediate, attributed to contributions from conformational flexibility and entropy. Moreover, we found that protonation of the scissile bond nitrogen occurs via proton transfer from a Zn(II)-coordinated hydroxide rather than from a solvent water molecule. Following C-N bond cleavage, the C-terminus remains coordinated to the catalytic Zn(II), while the N-terminus forms a hydrogen bond with a solvent water molecule. Subsequently, the release of the C-terminus is facilitated by the coordination of a water molecule. Our study underscores the pivotal role of protein conformational dynamics at physiological temperature in stabilizing the transition state of the rate-limiting step and key intermediates, compared to the corresponding reaction in solution. These fundamental insights into the mechanism of collagen degradation provide valuable guidance for the development of MMP-1-specific inhibitors.
由依赖锌(II)的基质金属蛋白酶(MMPs)催化的胶原水解是一个关键的生理过程。尽管之前对 MMP 介导的胶原蛋白水解催化机制进行了计算研究,但在生理温度下构象取样和熵贡献对酶解胶原蛋白的影响方面仍存在巨大的知识空白。在我们的综合多层次计算研究中,我们采用了量子力学/分子力学(QM/MM)元动力学(MetD)模拟,旨在弥合这一差距,并为 MMP-1 的催化机理提供有价值的见解。具体来说,我们比较了溶液中的全酶-底物复合物、溶液中的团簇和气相,以深入了解 MMP-1 催化胶原蛋白溶解的机制。与传统的静态势能面 QM/MM 反应路径研究相比,我们的发现揭示了在考虑热效应和系统动态演化时催化机制的显著差异。值得注意的是,我们观察到临界四面体中间体显著稳定,这归因于构象灵活性和熵的贡献。此外,我们还发现,裂键氮的质子化是通过与 Zn(II) 配位的氢氧化物而不是溶剂水分子的质子转移发生的。C-N 键裂解后,C 端仍与催化 Zn(II)配位,而 N 端则与溶剂水分子形成氢键。随后,水分子的配位促进了 C 端的释放。与溶液中的相应反应相比,我们的研究强调了蛋白质在生理温度下的构象动力学在稳定限速步骤的过渡状态和关键中间产物方面的关键作用。这些对胶原降解机制的基本见解为开发 MMP-1 特异性抑制剂提供了宝贵的指导。
{"title":"Novel Insights into the Catalytic Mechanism of Collagenolysis by Zn(II)-Dependent Matrix Metalloproteinase-1.","authors":"Koteswara Rao Gorantla, Anandhu Krishnan, Sodiq O Waheed, Ann Varghese, Isabella DiCastri, Ciara LaRouche, Meredith Paik, Gregg B Fields, Tatyana G Karabencheva-Christova","doi":"10.1021/acs.biochem.4c00076","DOIUrl":"10.1021/acs.biochem.4c00076","url":null,"abstract":"<p><p>Collagen hydrolysis, catalyzed by Zn(II)-dependent matrix metalloproteinases (MMPs), is a critical physiological process. Despite previous computational investigations into the catalytic mechanisms of MMP-mediated collagenolysis, a significant knowledge gap in understanding remains regarding the influence of conformational sampling and entropic contributions at physiological temperature on enzymatic collagenolysis. In our comprehensive multilevel computational study, employing quantum mechanics/molecular mechanics (QM/MM) metadynamics (MetD) simulations, we aimed to bridge this gap and provide valuable insights into the catalytic mechanism of MMP-1. Specifically, we compared the full enzyme-substrate complex in solution, clusters in solution, and gas-phase to elucidate insights into MMP-1-catalyzed collagenolysis. Our findings reveal significant differences in the catalytic mechanism when considering thermal effects and the dynamic evolution of the system, contrasting with conventional static potential energy surface QM/MM reaction path studies. Notably, we observed a significant stabilization of the critical tetrahedral intermediate, attributed to contributions from conformational flexibility and entropy. Moreover, we found that protonation of the scissile bond nitrogen occurs via proton transfer from a Zn(II)-coordinated hydroxide rather than from a solvent water molecule. Following C-N bond cleavage, the C-terminus remains coordinated to the catalytic Zn(II), while the N-terminus forms a hydrogen bond with a solvent water molecule. Subsequently, the release of the C-terminus is facilitated by the coordination of a water molecule. Our study underscores the pivotal role of protein conformational dynamics at physiological temperature in stabilizing the transition state of the rate-limiting step and key intermediates, compared to the corresponding reaction in solution. These fundamental insights into the mechanism of collagen degradation provide valuable guidance for the development of MMP-1-specific inhibitors.</p>","PeriodicalId":28,"journal":{"name":"Biochemistry Biochemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11309001/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141496312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}