Publication Date:
2010-05-25
Description:
The three-dimensional structures of proteins often show a modular architecture comprised of discrete structural regions or domains. Cooperative communication between these regions is important for catalysis, regulation and efficient folding; lack of coupling has been implicated in the formation of fibrils and other misfolding pathologies. How different structural regions of a protein communicate and contribute to a protein's overall energetics and folding, however, is still poorly understood. Here we use a single-molecule optical tweezers approach to induce the selective unfolding of particular regions of T4 lysozyme and monitor the effect on other regions not directly acted on by force. We investigate how the topological organization of a protein (the order of structural elements along the sequence) affects the coupling and folding cooperativity between its domains. To probe the status of the regions not directly subjected to force, we determine the free energy changes during mechanical unfolding using Crooks' fluctuation theorem. We pull on topological variants (circular permutants) and find that the topological organization of the polypeptide chain critically determines the folding cooperativity between domains and thus what parts of the folding/unfolding landscape are explored. We speculate that proteins may have evolved to select certain topologies that increase coupling between regions to avoid areas of the landscape that lead to kinetic trapping and misfolding.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2911970/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2911970/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shank, Elizabeth A -- Cecconi, Ciro -- Dill, Jesse W -- Marqusee, Susan -- Bustamante, Carlos -- GM 32543/GM/NIGMS NIH HHS/ -- GM 50945/GM/NIGMS NIH HHS/ -- R01 GM050945/GM/NIGMS NIH HHS/ -- R01 GM050945-17/GM/NIGMS NIH HHS/ -- England -- Nature. 2010 Jun 3;465(7298):637-40. doi: 10.1038/nature09021. Epub 2010 May 23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20495548" target="_blank"〉PubMed〈/a〉
Keywords:
Allosteric Regulation
;
Bacteriophage T4/*enzymology
;
Models, Molecular
;
Mutant Proteins/chemistry/genetics/metabolism
;
Optical Tweezers
;
Probability
;
Protein Denaturation
;
*Protein Folding
;
Protein Structure, Tertiary
;
Viral Proteins/*chemistry/genetics/*metabolism
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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