M Carmen Salinas-Garcia, Marina Plaza-Garrido, Jose C Martinez, Ana Camara-Artigas
{"title":"通过铰链环诱变了解c-Src SH3结构域交换。","authors":"M Carmen Salinas-Garcia, Marina Plaza-Garrido, Jose C Martinez, Ana Camara-Artigas","doi":"10.1107/S2059798325006977","DOIUrl":null,"url":null,"abstract":"<p><p>The c-Src SH3 domain is one of the best-characterized modular domains from a biophysical and structural point of view. This SH3 domain displays noncanonical alternative folding, forming 3D domain-swapped oligomers and amyloid fibrils. These features make this small protein an ideal model for studying these phenomena. Residues in the regions that favour unfolding of the monomer and those in the hinge loop have been deeply studied in proteins undergoing 3D domain swapping. To study the role of these residues in the unfolding of the c-Src SH3 domain, we have constructed several chimeric proteins by interchanging residues in the RT and n-Src loops between the c-Src SH3 and Abl SH3 domains. The RT (the region between β1 and β2) and n-Src (the region between β2 and β3) loops create two sides of the shallow hydrophobic groove where proline-rich motif sequences bind to the SH3 domain. In addition to the structural information, we have performed a biophysical characterization of these chimeric constructs. The c-Src SH3 domain bearing the loops of the Abl SH3 shows minor changes in stability. Interestingly, these replacements do not prevent the formation of domain-swapped dimers. However, the interchange of one or two loops within the Abl SH3 domain produces a noticeable reduction in its stability but does not promote the formation of 3D domain-swapped oligomers. Thus, our results indicate that although the composition of the hinge loop is likely to play a role in the interchange of structural elements to form the intertwined dimers, it is not the sole driving force in their formation.</p>","PeriodicalId":7116,"journal":{"name":"Acta Crystallographica. Section D, Structural Biology","volume":"81 Pt 9","pages":"492-510"},"PeriodicalIF":3.8000,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12400191/pdf/","citationCount":"0","resultStr":"{\"title\":\"Understanding domain swapping in the c-Src SH3 domain through hinge-loop mutagenesis.\",\"authors\":\"M Carmen Salinas-Garcia, Marina Plaza-Garrido, Jose C Martinez, Ana Camara-Artigas\",\"doi\":\"10.1107/S2059798325006977\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>The c-Src SH3 domain is one of the best-characterized modular domains from a biophysical and structural point of view. This SH3 domain displays noncanonical alternative folding, forming 3D domain-swapped oligomers and amyloid fibrils. These features make this small protein an ideal model for studying these phenomena. Residues in the regions that favour unfolding of the monomer and those in the hinge loop have been deeply studied in proteins undergoing 3D domain swapping. To study the role of these residues in the unfolding of the c-Src SH3 domain, we have constructed several chimeric proteins by interchanging residues in the RT and n-Src loops between the c-Src SH3 and Abl SH3 domains. The RT (the region between β1 and β2) and n-Src (the region between β2 and β3) loops create two sides of the shallow hydrophobic groove where proline-rich motif sequences bind to the SH3 domain. In addition to the structural information, we have performed a biophysical characterization of these chimeric constructs. The c-Src SH3 domain bearing the loops of the Abl SH3 shows minor changes in stability. Interestingly, these replacements do not prevent the formation of domain-swapped dimers. However, the interchange of one or two loops within the Abl SH3 domain produces a noticeable reduction in its stability but does not promote the formation of 3D domain-swapped oligomers. Thus, our results indicate that although the composition of the hinge loop is likely to play a role in the interchange of structural elements to form the intertwined dimers, it is not the sole driving force in their formation.</p>\",\"PeriodicalId\":7116,\"journal\":{\"name\":\"Acta Crystallographica. Section D, Structural Biology\",\"volume\":\"81 Pt 9\",\"pages\":\"492-510\"},\"PeriodicalIF\":3.8000,\"publicationDate\":\"2025-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12400191/pdf/\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Acta Crystallographica. 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Understanding domain swapping in the c-Src SH3 domain through hinge-loop mutagenesis.
The c-Src SH3 domain is one of the best-characterized modular domains from a biophysical and structural point of view. This SH3 domain displays noncanonical alternative folding, forming 3D domain-swapped oligomers and amyloid fibrils. These features make this small protein an ideal model for studying these phenomena. Residues in the regions that favour unfolding of the monomer and those in the hinge loop have been deeply studied in proteins undergoing 3D domain swapping. To study the role of these residues in the unfolding of the c-Src SH3 domain, we have constructed several chimeric proteins by interchanging residues in the RT and n-Src loops between the c-Src SH3 and Abl SH3 domains. The RT (the region between β1 and β2) and n-Src (the region between β2 and β3) loops create two sides of the shallow hydrophobic groove where proline-rich motif sequences bind to the SH3 domain. In addition to the structural information, we have performed a biophysical characterization of these chimeric constructs. The c-Src SH3 domain bearing the loops of the Abl SH3 shows minor changes in stability. Interestingly, these replacements do not prevent the formation of domain-swapped dimers. However, the interchange of one or two loops within the Abl SH3 domain produces a noticeable reduction in its stability but does not promote the formation of 3D domain-swapped oligomers. Thus, our results indicate that although the composition of the hinge loop is likely to play a role in the interchange of structural elements to form the intertwined dimers, it is not the sole driving force in their formation.
期刊介绍:
Acta Crystallographica Section D welcomes the submission of articles covering any aspect of structural biology, with a particular emphasis on the structures of biological macromolecules or the methods used to determine them.
Reports on new structures of biological importance may address the smallest macromolecules to the largest complex molecular machines. These structures may have been determined using any structural biology technique including crystallography, NMR, cryoEM and/or other techniques. The key criterion is that such articles must present significant new insights into biological, chemical or medical sciences. The inclusion of complementary data that support the conclusions drawn from the structural studies (such as binding studies, mass spectrometry, enzyme assays, or analysis of mutants or other modified forms of biological macromolecule) is encouraged.
Methods articles may include new approaches to any aspect of biological structure determination or structure analysis but will only be accepted where they focus on new methods that are demonstrated to be of general applicability and importance to structural biology. Articles describing particularly difficult problems in structural biology are also welcomed, if the analysis would provide useful insights to others facing similar problems.