Propensities of peptides containing the Asn ‐Gly segment to form β‐turn and β‐hairpin structures

ABSTRACT
The propensities of peptides that contain the Asn‐Gly segment to form β‐turn and β‐hairpin structures were explored using the density functional methods and the implicit solvation model in CH2Cl2 and water. The populations of preferred β‐turn structures varied depending on the sequence and solvent polarity. In solution, β‐hairpin structures with βI′ turn motifs were most preferred for the heptapeptides containing the Asn‐Gly segment regardless of the sequence of the strands. These preferences in solution are consistent with the corresponding X‐ray structures. The sequence, H‐bond strengths, solvent polarity, and conformational flexibility appeared to interact to determine the preferred β‐hairpin structure of each heptapeptide, although the β‐turn segments played a role in promoting the formation of β‐hairpin structures and the β‐hairpin propensity varied. In the heptapeptides containing the Asn‐Gly segment, the β‐hairpin formation was enthalpically favored and entropically disfavored at 25°C in water. The calculated results for β‐turns and β‐hairpins containing the Asn‐Gly segment imply that these structural preferences may be useful for the design of bioactive macrocyclic peptides containing β‐hairpin mimics and the design of binding epitopes for protein–protein and protein–nucleic acid recognitions. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 653–664, 2016.

Source: Biopolymers - June 17, 2016 Category: Biochemistry Authors: Young Kee Kang, In Kee Yoo Tags: Article Source Type: research