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Thermodynamics of binding by calmodulin correlates with target peptide α‐helical propensity
Author(s) -
Dunlap Tori B.,
Kirk Jessime M.,
Pena Emily A.,
Yoder Meghan S.,
Creamer Trevor P.
Publication year - 2013
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.24215
Subject(s) - calmodulin , affinities , chemistry , binding affinities , peptide , plasma protein binding , binding site , biophysics , stereochemistry , biochemistry , biology , enzyme , receptor
Abstract In this work, we have examined contributions to the thermodynamics of calmodulin (CaM) binding from the intrinsic propensity for target peptides to adopt an α‐helical conformation. CaM target sequences are thought to commonly reside in disordered regions within proteins. Using the ability of TFE to induce α‐helical structure as a proxy, the six peptides studied range from having almost no propensity to adopt α‐helical structure through to a very high propensity. This despite all six peptides having similar CaM‐binding affinities. Our data indicate there is some correlation between the deduced propensities and the thermodynamics of CaM binding. This finding implies that molecular recognition features, such as CaM target sequences, may possess a broad range of propensities to adopt local structure. Given that these peptides bind to CaM with similar affinities, the data suggest that having a higher propensity to adopt α‐helical structure does not necessarily result in tighter binding, and that the mechanism of CaM binding is very dependent on the nature of the substrate sequence. Proteins 2013. © 2012 Wiley Periodicals, Inc.