Pub Date : 2025-01-02DOI: 10.1016/j.str.2024.12.006
Thushara Nethramangalath, Loren W. Runnels
In this issue of Structure, Ma et al.1 apply the artificial intelligence system AlphaFold2, which was designed to predict three-dimensional protein structures from amino acid sequences with atomic accuracy, to model the conformal dynamics of the prokaryotic TpCorC and human CNNM2 and CNNM4 transporters, providing mechanistic insight into how sodium drives magnesium efflux.
{"title":"AI decodes CNNM Na+/Mg2+ exchange","authors":"Thushara Nethramangalath, Loren W. Runnels","doi":"10.1016/j.str.2024.12.006","DOIUrl":"https://doi.org/10.1016/j.str.2024.12.006","url":null,"abstract":"In this issue of <em>Structure</em>, Ma et al.<span><span><sup>1</sup></span></span> apply the artificial intelligence system AlphaFold2, which was designed to predict three-dimensional protein structures from amino acid sequences with atomic accuracy, to model the conformal dynamics of the prokaryotic TpCorC and human CNNM2 and CNNM4 transporters, providing mechanistic insight into how sodium drives magnesium efflux.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"25 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-02DOI: 10.1016/j.str.2024.12.007
Anand Srivastavava
In this issue of Structure, Soteriou et al.1 use cell biology, in vitro reconstitution approaches, and molecular dynamics (MD) simulations to characterize the membrane association of AKT1. The authors show that the AKT1 pleckstrin homology domain contains two essential and cooperative PI(3,4,5)P3-binding sites that enable stable membrane binding of AKT1 in the requisite orientation required for effective downstream signaling.
{"title":"It takes two to tango: The second membrane-binding site in peripheral proteins","authors":"Anand Srivastavava","doi":"10.1016/j.str.2024.12.007","DOIUrl":"https://doi.org/10.1016/j.str.2024.12.007","url":null,"abstract":"In this issue of <em>Structure</em>, Soteriou et al.<span><span><sup>1</sup></span></span> use cell biology, <em>in vitro</em> reconstitution approaches, and molecular dynamics (MD) simulations to characterize the membrane association of AKT1. The authors show that the AKT1 pleckstrin homology domain contains two essential and cooperative PI(3,4,5)P<sub>3</sub>-binding sites that enable stable membrane binding of AKT1 in the requisite orientation required for effective downstream signaling.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"66 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-02DOI: 10.1016/j.str.2024.12.005
Esko Oksanen
Lysozyme is a model system for crystallographers. In this issue of Structure, Ramos et al. report atomic resolution neutron structures of lysozyme, which unambiguously show the protonation states and hydrogen-bonding networks of the active site. This resolves mechanistic questions that have been debated for decades and provides a unique view to a protein at atomic detail.
{"title":"Lysozyme revisited","authors":"Esko Oksanen","doi":"10.1016/j.str.2024.12.005","DOIUrl":"https://doi.org/10.1016/j.str.2024.12.005","url":null,"abstract":"Lysozyme is a model system for crystallographers. In this issue of <em>Structure</em>, Ramos et al. report atomic resolution neutron structures of lysozyme, which unambiguously show the protonation states and hydrogen-bonding networks of the active site. This resolves mechanistic questions that have been debated for decades and provides a unique view to a protein at atomic detail.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"23 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-30DOI: 10.1016/j.str.2024.12.001
Xuan Ge, Jinqi Ren, Kewei Gu, Weibin Gong, Kang Shen, Wei Feng
BORC (BLOC-one-related complex) is a hetero-octameric complex, consisting of eight coiled-coil proteins (BORCS1–8). BORC controls lysosomal and synaptic vesicle transport and positioning by recruiting ARL8. The structural mechanisms underlying BORC assembly and ARL8 activation remain unclear. Here, we reconstitute and construct the structural model of this hetero-octameric complex. We find that BORC adopts an extended, rod-like structure made of coiled coils. Two hemicomplexes, each containing four subunits, are joined end-to-end to form the holocomplex. Within each hemicomplex, BORCS1/4/6/8 or BORCS2/3/5/7 assembles into similar helical bundles. We further study how BORC is built and discover a hierarchical assembly process in which BORCS1/2/3/5 forms the core scaffold and recruits other subunits. Mutations in the inter-hemicomplex interfaces result in two hemicomplexes. The association of ARL8 may require the proper assembly of BORC and is primarily mediated by BORCS5. These results provide guidance for further understanding of the biology of BORC.
{"title":"The structure and assembly of the hetero-octameric BLOC-one-related complex","authors":"Xuan Ge, Jinqi Ren, Kewei Gu, Weibin Gong, Kang Shen, Wei Feng","doi":"10.1016/j.str.2024.12.001","DOIUrl":"https://doi.org/10.1016/j.str.2024.12.001","url":null,"abstract":"BORC (BLOC-one-related complex) is a hetero-octameric complex, consisting of eight coiled-coil proteins (BORCS1–8). BORC controls lysosomal and synaptic vesicle transport and positioning by recruiting ARL8. The structural mechanisms underlying BORC assembly and ARL8 activation remain unclear. Here, we reconstitute and construct the structural model of this hetero-octameric complex. We find that BORC adopts an extended, rod-like structure made of coiled coils. Two hemicomplexes, each containing four subunits, are joined end-to-end to form the holocomplex. Within each hemicomplex, BORCS1/4/6/8 or BORCS2/3/5/7 assembles into similar helical bundles. We further study how BORC is built and discover a hierarchical assembly process in which BORCS1/2/3/5 forms the core scaffold and recruits other subunits. Mutations in the inter-hemicomplex interfaces result in two hemicomplexes. The association of ARL8 may require the proper assembly of BORC and is primarily mediated by BORCS5. These results provide guidance for further understanding of the biology of BORC.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"168 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-30DOI: 10.1016/j.str.2024.12.004
, Soumyananda Chakraborti, Sucharita Dey
Ferritins are ubiquitous and play a critical role in iron homeostasis. They are classified into four main subfamilies: classical, bacterial, bacterioferritin, and Dps. These are characterized by subunits with a four-helical bundle domain and interact through three distinct regions—one antiparallel interface (IntA) and two perpendicular interfaces (IntB and IntC), collectively forming a cage-like structure. Here, we attempt to characterize the variability of these interfaces across subfamilies. We found that IntA is essential for the dimeric unit assembly and is likely to assemble first, followed by the smaller interfaces of IntB and IntC (in any order), which are crucial for cage formation. These interfaces are unique in that they are less packed, although chemically stable, and their size lies between that of protein-protein complex and obligate homodimers. This study provides a detailed exploration of the ferritin interfaces, offering insights into their assembly and their importance as carrier proteins.
{"title":"Physicochemical features of subunit interfaces and their role in self-assembly across the ferritin superfamily","authors":", Soumyananda Chakraborti, Sucharita Dey","doi":"10.1016/j.str.2024.12.004","DOIUrl":"https://doi.org/10.1016/j.str.2024.12.004","url":null,"abstract":"Ferritins are ubiquitous and play a critical role in iron homeostasis. They are classified into four main subfamilies: classical, bacterial, bacterioferritin, and Dps. These are characterized by subunits with a four-helical bundle domain and interact through three distinct regions—one antiparallel interface (IntA) and two perpendicular interfaces (IntB and IntC), collectively forming a cage-like structure. Here, we attempt to characterize the variability of these interfaces across subfamilies. We found that IntA is essential for the dimeric unit assembly and is likely to assemble first, followed by the smaller interfaces of IntB and IntC (in any order), which are crucial for cage formation. These interfaces are unique in that they are less packed, although chemically stable, and their size lies between that of protein-protein complex and obligate homodimers. This study provides a detailed exploration of the ferritin interfaces, offering insights into their assembly and their importance as carrier proteins.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"65 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-30DOI: 10.1016/j.str.2024.12.002
Hao Huang, Wenning Zhu, Bin Huang, Ziyang Fu, Yuxian Xiong, Dan Cao, Yuxin Ye, Qing Chang, Wenqi Li, Long Li, Huan Zhou, Xiaogang Niu, Wei Zhang
The E2/E3 hybrid enzyme UBE2O plays important roles in key biological events, but its autoubiquitination mechanism remains largely unclear. In this study, we determined the crystal structures of full-length (FL) UBE2O from Trametes pubescens (tp) and its ubiquitin-conjugating (UBC) domain. The dimeric FL-tpUBE2O structure revealed interdomain interactions between the conserved regions (CR1-CR2) and UBC. The dimeric intermolecular and canonical ubiquitin/UBC interactions are mechanistically important for UBE2O functions in catalyzing the formation of free polyubiquitin chains and substrate ubiquitination. Beyond dimerization, autoubiquitination within the CR1-CR2 domain also regulates tpUBE2O activity. Additionally, we show that tpUBE2O catalyzes the formation of all seven types of polyubiquitin chains in vitro. The CR1-CR2/UBC and canonical ubiquitin/UBC interactions are important for the polyubiquitination of AMP-activated protein kinase α2 (AMPKα2) by human UBE2O (hUBE2O), which leads to tumorigenesis. These structural insights lay the groundwork for understanding UBE2O’s mechanisms and developing structure-based therapeutics targeting UBE2O.
{"title":"Structural insights into the biochemical mechanism of the E2/E3 hybrid enzyme UBE2O","authors":"Hao Huang, Wenning Zhu, Bin Huang, Ziyang Fu, Yuxian Xiong, Dan Cao, Yuxin Ye, Qing Chang, Wenqi Li, Long Li, Huan Zhou, Xiaogang Niu, Wei Zhang","doi":"10.1016/j.str.2024.12.002","DOIUrl":"https://doi.org/10.1016/j.str.2024.12.002","url":null,"abstract":"The E2/E3 hybrid enzyme UBE2O plays important roles in key biological events, but its autoubiquitination mechanism remains largely unclear. In this study, we determined the crystal structures of full-length (FL) UBE2O from <em>Trametes pubescens</em> (tp) and its ubiquitin-conjugating (UBC) domain. The dimeric FL-tpUBE2O structure revealed interdomain interactions between the conserved regions (CR1-CR2) and UBC. The dimeric intermolecular and canonical ubiquitin/UBC interactions are mechanistically important for UBE2O functions in catalyzing the formation of free polyubiquitin chains and substrate ubiquitination. Beyond dimerization, autoubiquitination within the CR1-CR2 domain also regulates tpUBE2O activity. Additionally, we show that tpUBE2O catalyzes the formation of all seven types of polyubiquitin chains <em>in vitro</em>. The CR1-CR2/UBC and canonical ubiquitin/UBC interactions are important for the polyubiquitination of AMP-activated protein kinase α2 (AMPKα2) by human UBE2O (hUBE2O), which leads to tumorigenesis. These structural insights lay the groundwork for understanding UBE2O’s mechanisms and developing structure-based therapeutics targeting UBE2O.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"81 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The solute carrier family 15 members 3 and 4 (SLC15A3 and SLC15A4) are closely related endolysosomal peptide transporters that transport free histidine and certain dipeptides from the lumen to cytosol. Besides, SLC15A4 also functions as a scaffold protein for the recruitment of the adapter TASL for interferon regulatory factor 5 (IRF5) activation downstream of innate immune TLR7-9 signaling. However, the molecular basis for the substrate recognition and TASL recruitment by these membrane proteins is not well understood. Here, we report the cryoelectron microscopy (cryo-EM) structure of apo SLC15A3 and structures of SLC15A4 in the absence or presence of the substrate, revealing the specific dipeptide recognition mechanism. Each SLC15A3 and SLC15A4 protomer adopts an outward-facing conformation. Furthermore, we also present the cryo-EM structure of a SLC15A4-TASL complex. The N terminal region of TASL forms a helical structure that inserts deeply into the inward-facing cavity of SLC15A4.
{"title":"The structures of the peptide transporters SLC15A3 and SLC15A4 reveal the recognition mechanisms for substrate and TASL","authors":"Zhikuan Zhang, Shota Kasai, Kentaro Sakaniwa, Akiko Fujimura, Umeharu Ohto, Toshiyuki Shimizu","doi":"10.1016/j.str.2024.11.019","DOIUrl":"https://doi.org/10.1016/j.str.2024.11.019","url":null,"abstract":"The solute carrier family 15 members 3 and 4 (SLC15A3 and SLC15A4) are closely related endolysosomal peptide transporters that transport free histidine and certain dipeptides from the lumen to cytosol. Besides, SLC15A4 also functions as a scaffold protein for the recruitment of the adapter TASL for interferon regulatory factor 5 (IRF5) activation downstream of innate immune TLR7-9 signaling. However, the molecular basis for the substrate recognition and TASL recruitment by these membrane proteins is not well understood. Here, we report the cryoelectron microscopy (cryo-EM) structure of apo SLC15A3 and structures of SLC15A4 in the absence or presence of the substrate, revealing the specific dipeptide recognition mechanism. Each SLC15A3 and SLC15A4 protomer adopts an outward-facing conformation. Furthermore, we also present the cryo-EM structure of a SLC15A4-TASL complex. The N terminal region of TASL forms a helical structure that inserts deeply into the inward-facing cavity of SLC15A4.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"61 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.1016/j.str.2024.11.014
Matthias Günther, Jana Sticht, Christian Freund, Thomas Höfer
Major histocompatibility complex class II (MHC-II) presents antigens to T helper cells. The spectrum of presented peptides is regulated by the exchange catalyst human leukocyte antigen DM (HLA-DM), which dissociates peptide-MHC-II complexes in the endosome. How susceptible a peptide is to HLA-DM is mechanistically not understood. Here, we present a data-driven mathematical model for the conformational landscape of MHC-II that explains the wide range of measured HLA-DM susceptibilities and predicts why some peptides are largely HLA-DM-resistant. We find that the conformational plasticity of MHC-II mediates both allosteric competition and cooperation between peptide and HLA-DM. Competition causes HLA-DM susceptibility to be proportional to the intrinsic peptide off-rate. Remarkably, diverse MHC-II allotypes with conserved HLA-DM interactions show a universal linear susceptibility function. However, HLA-DM-resistant peptides deviate from this susceptibility function; we predict resistance to be caused by fast peptide association with MHC-II. Thus, our study provides quantitative insight into peptide and MHC-II allotype parameters that shape class-II antigen presentation.
{"title":"Antigen presentation by MHC-II is shaped by competitive and cooperative allosteric mechanisms of peptide exchange","authors":"Matthias Günther, Jana Sticht, Christian Freund, Thomas Höfer","doi":"10.1016/j.str.2024.11.014","DOIUrl":"https://doi.org/10.1016/j.str.2024.11.014","url":null,"abstract":"Major histocompatibility complex class II (MHC-II) presents antigens to T helper cells. The spectrum of presented peptides is regulated by the exchange catalyst human leukocyte antigen DM (HLA-DM), which dissociates peptide-MHC-II complexes in the endosome. How susceptible a peptide is to HLA-DM is mechanistically not understood. Here, we present a data-driven mathematical model for the conformational landscape of MHC-II that explains the wide range of measured HLA-DM susceptibilities and predicts why some peptides are largely HLA-DM-resistant. We find that the conformational plasticity of MHC-II mediates both allosteric competition and cooperation between peptide and HLA-DM. Competition causes HLA-DM susceptibility to be proportional to the intrinsic peptide off-rate. Remarkably, diverse MHC-II allotypes with conserved HLA-DM interactions show a universal linear susceptibility function. However, HLA-DM-resistant peptides deviate from this susceptibility function; we predict resistance to be caused by fast peptide association with MHC-II. Thus, our study provides quantitative insight into peptide and MHC-II allotype parameters that shape class-II antigen presentation.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"20 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.1016/j.str.2024.11.018
Kavita A. Iyer, Takuya Kobayashi, Takashi Murayama, Montserrat Samsó
Mutations in the skeletal isoform of the ryanodine receptor 1 (RyR1) pose grave risks during anesthesia or treatment with succinylcholine muscle relaxants. These can trigger a potentially lethal malignant hyperthermia (MH) episode via intracellular calcium increase mainly from RyR1 channel leakage. Dantrolene is the only known treatment option to prevent death. The main target of dantrolene is RyR1; however, little is known about the mechanism of inhibition. Cryoelectron microscopy (cryo-EM) structures of dantrolene bound to the severe MH Y522S RyR1 mutant in the closed and open states at 2.5–3.3 Å resolution revealed that the drug binds to the channel’s cytoplasmic assembly, far from the ion gate, interacting with residues W882, W996, and R1000 in the P1 domain. The finding was validated by Ca2+ imaging and [3H]ryanodine binding in wild-type (WT) and alanine mutants. Dantrolene reduced channel opening probability by restricting the central activation module, “cooling down” the primed conformation caused by the mutation.
{"title":"Dantrolene inhibition of ryanodine receptor 1 carrying the severe malignant hyperthermia mutation Y522S visualized by cryo-EM","authors":"Kavita A. Iyer, Takuya Kobayashi, Takashi Murayama, Montserrat Samsó","doi":"10.1016/j.str.2024.11.018","DOIUrl":"https://doi.org/10.1016/j.str.2024.11.018","url":null,"abstract":"Mutations in the skeletal isoform of the ryanodine receptor 1 (RyR1) pose grave risks during anesthesia or treatment with succinylcholine muscle relaxants. These can trigger a potentially lethal malignant hyperthermia (MH) episode via intracellular calcium increase mainly from RyR1 channel leakage. Dantrolene is the only known treatment option to prevent death. The main target of dantrolene is RyR1; however, little is known about the mechanism of inhibition. Cryoelectron microscopy (cryo-EM) structures of dantrolene bound to the severe MH Y522S RyR1 mutant in the closed and open states at 2.5–3.3 Å resolution revealed that the drug binds to the channel’s cytoplasmic assembly, far from the ion gate, interacting with residues W882, W996, and R1000 in the P1 domain. The finding was validated by Ca<sup>2+</sup> imaging and [<sup>3</sup>H]ryanodine binding in wild-type (WT) and alanine mutants. Dantrolene reduced channel opening probability by restricting the central activation module, “cooling down” the primed conformation caused by the mutation.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"112 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-19DOI: 10.1016/j.str.2024.11.017
Sven Larsen-Ledet, Søren Lindemose, Aleksandra Panfilova, Sarah Gersing, Caroline H. Suhr, Aitana Victoria Genzor, Heleen Lanters, Sofie V. Nielsen, Kresten Lindorff-Larsen, Jakob R. Winther, Amelie Stein, Rasmus Hartmann-Petersen
Gene variants resulting in insertions or deletions of amino acid residues (indels) have important consequences for evolution and are often linked to disease, yet, compared to missense variants, the effects of indels are poorly understood and predicted. We developed a sensitive protein folding sensor based on the complementation of uracil auxotrophy in yeast by circular permutated orotate phosphoribosyltransferase (CPOP). The sensor reports on the folding of disease-linked missense variants and de-novo-designed proteins. Applying the folding sensor to a saturated library of single-residue indels in human dihydrofolate reductase (DHFR) revealed that most regions that tolerate indels are confined to internal loops, the termini, and a central α helix. Several indels are temperature sensitive, and folding is rescued upon binding to methotrexate. Rosetta and AlphaFold2 predictions correlate with the observed effects, suggesting that most indels destabilize the native fold and that these computational tools are useful for the classification of indels observed in population sequencing.
{"title":"Systematic characterization of indel variants using a yeast-based protein folding sensor","authors":"Sven Larsen-Ledet, Søren Lindemose, Aleksandra Panfilova, Sarah Gersing, Caroline H. Suhr, Aitana Victoria Genzor, Heleen Lanters, Sofie V. Nielsen, Kresten Lindorff-Larsen, Jakob R. Winther, Amelie Stein, Rasmus Hartmann-Petersen","doi":"10.1016/j.str.2024.11.017","DOIUrl":"https://doi.org/10.1016/j.str.2024.11.017","url":null,"abstract":"Gene variants resulting in insertions or deletions of amino acid residues (indels) have important consequences for evolution and are often linked to disease, yet, compared to missense variants, the effects of indels are poorly understood and predicted. We developed a sensitive protein folding sensor based on the complementation of uracil auxotrophy in yeast by circular permutated orotate phosphoribosyltransferase (CPOP). The sensor reports on the folding of disease-linked missense variants and <em>de</em>-<em>novo</em>-designed proteins. Applying the folding sensor to a saturated library of single-residue indels in human dihydrofolate reductase (DHFR) revealed that most regions that tolerate indels are confined to internal loops, the termini, and a central α helix. Several indels are temperature sensitive, and folding is rescued upon binding to methotrexate. Rosetta and AlphaFold2 predictions correlate with the observed effects, suggesting that most indels destabilize the native fold and that these computational tools are useful for the classification of indels observed in population sequencing.","PeriodicalId":22168,"journal":{"name":"Structure","volume":"87 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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