Pub Date : 2024-05-21DOI: 10.1038/s41594-024-01316-4
Yihe Huang, Sushant Kumar, Junuk Lee, Wei Lü, Juan Du
Channel enzymes represent a class of ion channels with enzymatic activity directly or indirectly linked to their channel function. We investigated a TRPM2 chanzyme from choanoflagellates that integrates two seemingly incompatible functions into a single peptide: a channel module activated by ADP-ribose with high open probability and an enzyme module (NUDT9-H domain) consuming ADP-ribose at a remarkably slow rate. Using time-resolved cryogenic-electron microscopy, we captured a complete series of structural snapshots of gating and catalytic cycles, revealing the coupling mechanism between channel gating and enzymatic activity. The slow kinetics of the NUDT9-H enzyme module confers a self-regulatory mechanism: ADPR binding triggers NUDT9-H tetramerization, promoting channel opening, while subsequent hydrolysis reduces local ADPR, inducing channel closure. We further demonstrated how the NUDT9-H domain has evolved from a structurally semi-independent ADP-ribose hydrolase module in early species to a fully integrated component of a gating ring essential for channel activation in advanced species. Using time-resolved cryo-EM, the authors capture complete structural snapshots of the enzymatic cycle coupled with channel gating in a TRPM-type channel enzyme.
{"title":"Coupling enzymatic activity and gating in an ancient TRPM chanzyme and its molecular evolution","authors":"Yihe Huang, Sushant Kumar, Junuk Lee, Wei Lü, Juan Du","doi":"10.1038/s41594-024-01316-4","DOIUrl":"10.1038/s41594-024-01316-4","url":null,"abstract":"Channel enzymes represent a class of ion channels with enzymatic activity directly or indirectly linked to their channel function. We investigated a TRPM2 chanzyme from choanoflagellates that integrates two seemingly incompatible functions into a single peptide: a channel module activated by ADP-ribose with high open probability and an enzyme module (NUDT9-H domain) consuming ADP-ribose at a remarkably slow rate. Using time-resolved cryogenic-electron microscopy, we captured a complete series of structural snapshots of gating and catalytic cycles, revealing the coupling mechanism between channel gating and enzymatic activity. The slow kinetics of the NUDT9-H enzyme module confers a self-regulatory mechanism: ADPR binding triggers NUDT9-H tetramerization, promoting channel opening, while subsequent hydrolysis reduces local ADPR, inducing channel closure. We further demonstrated how the NUDT9-H domain has evolved from a structurally semi-independent ADP-ribose hydrolase module in early species to a fully integrated component of a gating ring essential for channel activation in advanced species. Using time-resolved cryo-EM, the authors capture complete structural snapshots of the enzymatic cycle coupled with channel gating in a TRPM-type channel enzyme.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 10","pages":"1509-1521"},"PeriodicalIF":12.5,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41594-024-01316-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141074084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-05-20DOI: 10.1038/s41594-024-01310-w
NAD(H) redox homeostasis has a fundamental role in cellular metabolism. We screened for potential modulators of NAD(H) using a genome-scale RNA interference (RNAi) approach combined with SoNar, a high-performance sensor that is sensitive to the redox state of NAD(H). Our analysis identified HES4 as a negative regulator of the NADH/NAD+ ratio that influences pyrimidine biosynthesis and exerts a potent oncogenic effect.
{"title":"HES4 controls redox balance and supports pyrimidine synthesis and tumor growth","authors":"","doi":"10.1038/s41594-024-01310-w","DOIUrl":"10.1038/s41594-024-01310-w","url":null,"abstract":"NAD(H) redox homeostasis has a fundamental role in cellular metabolism. We screened for potential modulators of NAD(H) using a genome-scale RNA interference (RNAi) approach combined with SoNar, a high-performance sensor that is sensitive to the redox state of NAD(H). Our analysis identified HES4 as a negative regulator of the NADH/NAD+ ratio that influences pyrimidine biosynthesis and exerts a potent oncogenic effect.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 9","pages":"1315-1316"},"PeriodicalIF":12.5,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141069458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-20DOI: 10.1038/s41594-024-01278-7
Daniela Rhodes
Hexasomes are non-canonical nucleosomes that package DNA with six instead of eight histones. First discovered 40 years ago as a consequence of transcription, two near-atomic-resolution cryo-EM structures of the hexasome in complex with the chromatin remodeler INO80 have now started to unravel its mechanistic impact on the regulatory landscape of chromatin. Loss of one histone H2A–H2B dimer converts inactive nucleosomes into distinct and favorable substrates for ATP-dependent chromatin remodeling. Hexasomes are non-canonical nucleosomes that package DNA with six instead of eight histones. Here, the author contextualizes two recent studies on the interplay of the chromatin remodeler INO80 with hexasomes with historical literature on the subject.
六聚体是一种非典型核小体，用六个而不是八个组蛋白包装 DNA。六聚体与染色质重塑剂 INO80 复合物的两个近原子分辨率低温电子显微镜结构于 40 年前首次被发现，现在已开始揭示其对染色质调控景观的机理影响。一个组蛋白 H2A-H2B 二聚体的缺失将非活性核小体转化为 ATP 依赖性染色质重塑的独特而有利的底物。
{"title":"To slide or not to slide: key role of the hexasome in chromatin remodeling revealed","authors":"Daniela Rhodes","doi":"10.1038/s41594-024-01278-7","DOIUrl":"10.1038/s41594-024-01278-7","url":null,"abstract":"Hexasomes are non-canonical nucleosomes that package DNA with six instead of eight histones. First discovered 40 years ago as a consequence of transcription, two near-atomic-resolution cryo-EM structures of the hexasome in complex with the chromatin remodeler INO80 have now started to unravel its mechanistic impact on the regulatory landscape of chromatin. Loss of one histone H2A–H2B dimer converts inactive nucleosomes into distinct and favorable substrates for ATP-dependent chromatin remodeling. Hexasomes are non-canonical nucleosomes that package DNA with six instead of eight histones. Here, the author contextualizes two recent studies on the interplay of the chromatin remodeler INO80 with hexasomes with historical literature on the subject.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 5","pages":"742-746"},"PeriodicalIF":16.8,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141071501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-20DOI: 10.1038/s41594-024-01309-3
Jing He, Aoxue Wang, Qin Zhao, Yejun Zou, Zhuo Zhang, Nannan Sha, Guofang Hou, Bei Zhou, Yi Yang, Tao Chen, Yuzheng Zhao, Yuhui Jiang
NADH/NAD+ redox balance is pivotal for cellular metabolism. Systematic identification of NAD(H) redox regulators, although currently lacking, would help uncover unknown effectors critically implicated in the coordination of growth metabolism. In this study, we performed a genome-scale RNA interference (RNAi) screen to globally survey the genes involved in redox modulation and identified the HES family bHLH transcription factor HES4 as a negative regulator of NADH/NAD+ ratio. Functionally, HES4 is shown to be crucial for maintaining mitochondrial electron transport chain (ETC) activity and pyrimidine synthesis. More specifically, HES4 directly represses transcription of SLC44A2 and SDS, thereby inhibiting mitochondrial choline oxidation and cytosolic serine deamination, respectively, which, in turn, ensures coenzyme Q reduction capacity for DHODH-mediated UMP synthesis and serine-derived dTMP production. Accordingly, inhibition of choline oxidation preserves mitochondrial serine catabolism and ETC-coupled redox balance. Furthermore, HES4 protein stability is enhanced under EGFR activation, and increased HES4 levels facilitate EGFR-driven tumor growth and predict poor prognosis of lung adenocarcinoma. These findings illustrate an unidentified mechanism, underlying pyrimidine biosynthesis in the intersection between serine and choline catabolism, and underscore the physiological importance of HES4 in tumor metabolism. The authors identify genes potentially involved in NAD(H) redox modulation and provide insight on major hit HES4, which uses its transcriptional repressive function to drive pyrimidine nucleotide biosynthesis and tumor growth.
{"title":"RNAi screens identify HES4 as a regulator of redox balance supporting pyrimidine synthesis and tumor growth","authors":"Jing He, Aoxue Wang, Qin Zhao, Yejun Zou, Zhuo Zhang, Nannan Sha, Guofang Hou, Bei Zhou, Yi Yang, Tao Chen, Yuzheng Zhao, Yuhui Jiang","doi":"10.1038/s41594-024-01309-3","DOIUrl":"10.1038/s41594-024-01309-3","url":null,"abstract":"NADH/NAD+ redox balance is pivotal for cellular metabolism. Systematic identification of NAD(H) redox regulators, although currently lacking, would help uncover unknown effectors critically implicated in the coordination of growth metabolism. In this study, we performed a genome-scale RNA interference (RNAi) screen to globally survey the genes involved in redox modulation and identified the HES family bHLH transcription factor HES4 as a negative regulator of NADH/NAD+ ratio. Functionally, HES4 is shown to be crucial for maintaining mitochondrial electron transport chain (ETC) activity and pyrimidine synthesis. More specifically, HES4 directly represses transcription of SLC44A2 and SDS, thereby inhibiting mitochondrial choline oxidation and cytosolic serine deamination, respectively, which, in turn, ensures coenzyme Q reduction capacity for DHODH-mediated UMP synthesis and serine-derived dTMP production. Accordingly, inhibition of choline oxidation preserves mitochondrial serine catabolism and ETC-coupled redox balance. Furthermore, HES4 protein stability is enhanced under EGFR activation, and increased HES4 levels facilitate EGFR-driven tumor growth and predict poor prognosis of lung adenocarcinoma. These findings illustrate an unidentified mechanism, underlying pyrimidine biosynthesis in the intersection between serine and choline catabolism, and underscore the physiological importance of HES4 in tumor metabolism. The authors identify genes potentially involved in NAD(H) redox modulation and provide insight on major hit HES4, which uses its transcriptional repressive function to drive pyrimidine nucleotide biosynthesis and tumor growth.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 9","pages":"1413-1425"},"PeriodicalIF":12.5,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141069478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-20DOI: 10.1038/s41594-024-01315-5
Ruisheng Xu, Yingjie Ning, Fandong Ren, Chenxia Gu, Zhengjiang Zhu, Xuefang Pan, Alexey V. Pshezhetsky, Jingpeng Ge, Jie Yu
Lysosomal transmembrane acetylation of heparan sulfates (HS) is catalyzed by HS acetyl-CoA:α-glucosaminide N-acetyltransferase (HGSNAT), whose dysfunction leads to lysosomal storage diseases. The mechanism by which HGSNAT, the sole non-hydrolase enzyme in HS degradation, brings cytosolic acetyl-coenzyme A (Ac-CoA) and lysosomal HS together for N-acyltransferase reactions remains unclear. Here, we present cryogenic-electron microscopy structures of HGSNAT alone, complexed with Ac-CoA and with acetylated products. These structures explain that Ac-CoA binding from the cytosolic side causes dimeric HGSNAT to form a transmembrane tunnel. Within this tunnel, catalytic histidine and asparagine approach the lumen and instigate the transfer of the acetyl group from Ac-CoA to the glucosamine group of HS. Our study unveils a transmembrane acetylation mechanism that may help advance therapeutic strategies targeting lysosomal storage diseases. This study reports the structure of lysosomal N-acetyltransferase HGSNAT providing insights into the mechanism of lysosomal transmembrane acetylation of heparan sulfate required for its catabolism.
{"title":"Structure and mechanism of lysosome transmembrane acetylation by HGSNAT","authors":"Ruisheng Xu, Yingjie Ning, Fandong Ren, Chenxia Gu, Zhengjiang Zhu, Xuefang Pan, Alexey V. Pshezhetsky, Jingpeng Ge, Jie Yu","doi":"10.1038/s41594-024-01315-5","DOIUrl":"10.1038/s41594-024-01315-5","url":null,"abstract":"Lysosomal transmembrane acetylation of heparan sulfates (HS) is catalyzed by HS acetyl-CoA:α-glucosaminide N-acetyltransferase (HGSNAT), whose dysfunction leads to lysosomal storage diseases. The mechanism by which HGSNAT, the sole non-hydrolase enzyme in HS degradation, brings cytosolic acetyl-coenzyme A (Ac-CoA) and lysosomal HS together for N-acyltransferase reactions remains unclear. Here, we present cryogenic-electron microscopy structures of HGSNAT alone, complexed with Ac-CoA and with acetylated products. These structures explain that Ac-CoA binding from the cytosolic side causes dimeric HGSNAT to form a transmembrane tunnel. Within this tunnel, catalytic histidine and asparagine approach the lumen and instigate the transfer of the acetyl group from Ac-CoA to the glucosamine group of HS. Our study unveils a transmembrane acetylation mechanism that may help advance therapeutic strategies targeting lysosomal storage diseases. This study reports the structure of lysosomal N-acetyltransferase HGSNAT providing insights into the mechanism of lysosomal transmembrane acetylation of heparan sulfate required for its catabolism.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 10","pages":"1502-1508"},"PeriodicalIF":12.5,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141069452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-20DOI: 10.1038/s41594-024-01327-1
This issue of Nature Structural & Molecular Biology presents studies investigating RNA processing, including mechanisms of splicing, biogenesis of the splicing machinery, decoding of mRNA by the ribosome, and deadenylation of mRNA for degradation. We are also delighted to be publishing News & Views and Comment pieces that reflect on these exciting advances in the field.
{"title":"The RNA world","authors":"","doi":"10.1038/s41594-024-01327-1","DOIUrl":"10.1038/s41594-024-01327-1","url":null,"abstract":"This issue of Nature Structural & Molecular Biology presents studies investigating RNA processing, including mechanisms of splicing, biogenesis of the splicing machinery, decoding of mRNA by the ribosome, and deadenylation of mRNA for degradation. We are also delighted to be publishing News & Views and Comment pieces that reflect on these exciting advances in the field.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 5","pages":"729-729"},"PeriodicalIF":16.8,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41594-024-01327-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141071499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-05-17DOI: 10.1038/s41594-024-01280-z
Sarah S. Henrikus, Marta H. Gross, Oliver Willhoft, Thomas Pühringer, Jacob S. Lewis, Allison W. McClure, Julia F. Greiwe, Giacomo Palm, Andrea Nans, John F. X. Diffley, Alessandro Costa
To prevent detrimental chromosome re-replication, DNA loading of a double hexamer of the minichromosome maintenance (MCM) replicative helicase is temporally separated from DNA unwinding. Upon S-phase transition in yeast, DNA unwinding is achieved in two steps: limited opening of the double helix and topological separation of the two DNA strands. First, Cdc45, GINS and Polε engage MCM to assemble a double CMGE with two partially separated hexamers that nucleate DNA melting. In the second step, triggered by Mcm10, two CMGEs separate completely, eject the lagging-strand template and cross paths. To understand Mcm10 during helicase activation, we used biochemical reconstitution with cryogenic electron microscopy. We found that Mcm10 splits the double CMGE by engaging the N-terminal homo-dimerization face of MCM. To eject the lagging strand, DNA unwinding is started from the N-terminal side of MCM while the hexamer channel becomes too narrow to harbor duplex DNA. Here the authors used cryogenic electron microscopy and biochemistry to understand how yeast Mcm10 exerts its essential role in DNA replication initiation, finding that it splits the double Cdc45-MCM-GINS-Polε structure. The lagging-strand template is ejected from each MCM ring as the central channel of the helicase becomes too tight to accommodate two DNA strands.
为了防止有害的染色体再复制，微型染色体维护（MCM）复制螺旋酶双六聚体的 DNA 加载与 DNA 解旋在时间上是分离的。在酵母的 S 期转换过程中，DNA 解旋分为两个步骤：双螺旋的有限开放和两条 DNA 链的拓扑分离。首先，Cdc45、GINS 和 Polε 与 MCM 结合，组装出带有两个部分分离的六聚体的双 CMGE，从而核化 DNA 熔化。第二步由 Mcm10 触发，两个 CMGE 完全分离，弹出滞后链模板并交叉。为了了解螺旋酶激活过程中的 Mcm10，我们使用了生化重组和低温电子显微镜。我们发现，Mcm10 通过与 MCM 的 N 端同源二聚化面接合来分裂双 CMGE。为了排出滞后链，DNA 从 MCM 的 N 端开始解旋，同时六聚体通道变得过于狭窄，无法容纳双链 DNA。
{"title":"Unwinding of a eukaryotic origin of replication visualized by cryo-EM","authors":"Sarah S. Henrikus, Marta H. Gross, Oliver Willhoft, Thomas Pühringer, Jacob S. Lewis, Allison W. McClure, Julia F. Greiwe, Giacomo Palm, Andrea Nans, John F. X. Diffley, Alessandro Costa","doi":"10.1038/s41594-024-01280-z","DOIUrl":"10.1038/s41594-024-01280-z","url":null,"abstract":"To prevent detrimental chromosome re-replication, DNA loading of a double hexamer of the minichromosome maintenance (MCM) replicative helicase is temporally separated from DNA unwinding. Upon S-phase transition in yeast, DNA unwinding is achieved in two steps: limited opening of the double helix and topological separation of the two DNA strands. First, Cdc45, GINS and Polε engage MCM to assemble a double CMGE with two partially separated hexamers that nucleate DNA melting. In the second step, triggered by Mcm10, two CMGEs separate completely, eject the lagging-strand template and cross paths. To understand Mcm10 during helicase activation, we used biochemical reconstitution with cryogenic electron microscopy. We found that Mcm10 splits the double CMGE by engaging the N-terminal homo-dimerization face of MCM. To eject the lagging strand, DNA unwinding is started from the N-terminal side of MCM while the hexamer channel becomes too narrow to harbor duplex DNA. Here the authors used cryogenic electron microscopy and biochemistry to understand how yeast Mcm10 exerts its essential role in DNA replication initiation, finding that it splits the double Cdc45-MCM-GINS-Polε structure. The lagging-strand template is ejected from each MCM ring as the central channel of the helicase becomes too tight to accommodate two DNA strands.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 8","pages":"1265-1276"},"PeriodicalIF":12.5,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41594-024-01280-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140953637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-05-16DOI: 10.1038/s41594-024-01317-3
Michael B. Cory, Allen Li, Christina M. Hurley, Peter J. Carman, Ruth A. Pumroy, Zachary M. Hostetler, Ryann M. Perez, Yarra Venkatesh, Xinning Li, Kushol Gupta, E. James Petersson, Rahul M. Kohli
The bacterial SOS response plays a key role in adaptation to DNA damage, including genomic stress caused by antibiotics. SOS induction begins when activated RecA*, an oligomeric nucleoprotein filament that forms on single-stranded DNA, binds to and stimulates autoproteolysis of the repressor LexA. Here, we present the structure of the complete Escherichia coli SOS signal complex, constituting full-length LexA bound to RecA*. We uncover an extensive interface unexpectedly including the LexA DNA-binding domain, providing a new molecular rationale for ordered SOS gene induction. We further find that the interface involves three RecA subunits, with a single residue in the central engaged subunit acting as a molecular key, inserting into an allosteric binding pocket to induce LexA cleavage. Given the pro-mutagenic nature of SOS activation, our structural and mechanistic insights provide a foundation for developing new therapeutics to slow the evolution of antibiotic resistance. Here, using cryo-EM, the authors reveal the mechanism by which RecA filamented on single-stranded DNA binds to and induces LexA cleavage, the key signal governing the bacterial DNA damage response pathway implicated in antibiotic resistance.
细菌的 SOS 反应在适应 DNA 损伤（包括抗生素引起的基因组压力）方面发挥着关键作用。当活化的 RecA*（一种在单链 DNA 上形成的寡聚核蛋白丝）与抑制因子 LexA 结合并刺激其自体蛋白水解时，SOS 诱导就开始了。在这里，我们展示了完整的大肠杆菌 SOS 信号复合体结构，它由与 RecA* 结合的全长 LexA 构成。我们意外地发现了一个包括 LexA DNA 结合域在内的广泛界面，为有序的 SOS 基因诱导提供了新的分子原理。我们进一步发现，该界面涉及三个 RecA 亚基，中央参与亚基中的一个残基充当了分子钥匙，插入异生结合口袋，诱导 LexA 分裂。鉴于 SOS 激活具有促突变的性质，我们在结构和机理方面的见解为开发减缓抗生素耐药性演变的新疗法奠定了基础。
{"title":"The LexA–RecA* structure reveals a cryptic lock-and-key mechanism for SOS activation","authors":"Michael B. Cory, Allen Li, Christina M. Hurley, Peter J. Carman, Ruth A. Pumroy, Zachary M. Hostetler, Ryann M. Perez, Yarra Venkatesh, Xinning Li, Kushol Gupta, E. James Petersson, Rahul M. Kohli","doi":"10.1038/s41594-024-01317-3","DOIUrl":"10.1038/s41594-024-01317-3","url":null,"abstract":"The bacterial SOS response plays a key role in adaptation to DNA damage, including genomic stress caused by antibiotics. SOS induction begins when activated RecA*, an oligomeric nucleoprotein filament that forms on single-stranded DNA, binds to and stimulates autoproteolysis of the repressor LexA. Here, we present the structure of the complete Escherichia coli SOS signal complex, constituting full-length LexA bound to RecA*. We uncover an extensive interface unexpectedly including the LexA DNA-binding domain, providing a new molecular rationale for ordered SOS gene induction. We further find that the interface involves three RecA subunits, with a single residue in the central engaged subunit acting as a molecular key, inserting into an allosteric binding pocket to induce LexA cleavage. Given the pro-mutagenic nature of SOS activation, our structural and mechanistic insights provide a foundation for developing new therapeutics to slow the evolution of antibiotic resistance. Here, using cryo-EM, the authors reveal the mechanism by which RecA filamented on single-stranded DNA binds to and induces LexA cleavage, the key signal governing the bacterial DNA damage response pathway implicated in antibiotic resistance.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 10","pages":"1522-1531"},"PeriodicalIF":12.5,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140949446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-14DOI: 10.1038/s41594-024-01312-8
Lori A. Passmore, Suyang Zhang
Since Nature Structural and Molecular Biology was started 30 years ago, our understanding of transcription and mRNA processing has been revolutionized through structural and mechanistic studies. Here, we present our personal views of the advances in understanding the production of mature eukaryotic mRNAs over the past decade.
{"title":"Mechanisms of transcription and RNA processing","authors":"Lori A. Passmore, Suyang Zhang","doi":"10.1038/s41594-024-01312-8","DOIUrl":"10.1038/s41594-024-01312-8","url":null,"abstract":"Since Nature Structural and Molecular Biology was started 30 years ago, our understanding of transcription and mRNA processing has been revolutionized through structural and mechanistic studies. Here, we present our personal views of the advances in understanding the production of mature eukaryotic mRNAs over the past decade.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 5","pages":"730-731"},"PeriodicalIF":16.8,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140919844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-13DOI: 10.1038/s41594-024-01308-4
Sara R. Downs, Bec Grace, Jeffrey A. Pleiss
Branch point selection is required for pre-mRNA splicing, and its mis-regulation is associated with many diseases. Two structural studies provide insights into the dynamics of active site formation and the spliceosomal proteins that may contribute to activation of the correct branch point in eukaryotic introns.
{"title":"Decoding branch points and unlocking splicing secrets","authors":"Sara R. Downs, Bec Grace, Jeffrey A. Pleiss","doi":"10.1038/s41594-024-01308-4","DOIUrl":"10.1038/s41594-024-01308-4","url":null,"abstract":"Branch point selection is required for pre-mRNA splicing, and its mis-regulation is associated with many diseases. Two structural studies provide insights into the dynamics of active site formation and the spliceosomal proteins that may contribute to activation of the correct branch point in eukaryotic introns.","PeriodicalId":49141,"journal":{"name":"Nature Structural & Molecular Biology","volume":"31 5","pages":"732-734"},"PeriodicalIF":16.8,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140915140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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