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Updated: May 16, 2026

Measuring Biomolecular DSC Profiles with Thermolabile Ligands to Rapidly Characterize Folding and Binding Interactions
Published on: November 21, 2017
Thermodynamics of binding by calmodulin correlates with target peptide α-helical propensity
Tori B Dunlap1, Jessime M Kirk, Emily A Pena
1Center for Structural Biology, Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536-0509, USA.
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.
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