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β‐strand recombination in tricalbin evolution and the origin of synaptotagmin‐like C2 domains
Author(s) -
Jiménez José L.,
Davletov Bazbek
Publication year - 2007
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.21449
Subject(s) - synaptotagmin 1 , biology , recombination , genetics , computational biology , topology (electrical circuits) , gene , mathematics , combinatorics , membrane , vesicle , synaptic vesicle
Two protein families involved in membrane traffic, tricalbins and synaptotagmins, contain several copies of C2 domains and are related based on their sequence and domain architecture. Paradoxically, tricalbin and synaptotagmin C2 domains belong to different structural types with apparent circular permutation of terminal β‐strands. To understand whether a topological switch took place, we analyzed tricalbin and synaptotagmin‐like C2 domains using two‐dimensional structural analysis. We found that yeast tricalbins contain five to six C2 domains. One of these C2 domains possesses many features of synaptotagmin‐like C2 domains and also carries a conserved C‐terminal strand that is similar to its structural equivalent in synaptotagmin‐like C2 domains, suggesting a structural permutation event. Indeed, among higher eukaryotes, animal tricalbins have evolved a C2 domain with synaptotagmin‐like topology indicating that the structural conversion has taken place. Investigation of plant synaptotagmins, however, proves that they are direct tricalbin orthologs. Our analysis shows that β‐strand recombination is a possible evolutionary mechanism to generate new structural topologies with altered functional properties. Proteins 2007. © 2007 Wiley‐Liss, Inc.