Effects of side chains in helix nucleation differ from helix propagation.

ABSTRACT: Helix-coil transition theory connects observable properties of the α-helix to an ensemble of microstates and provides a foundation for analyzing secondary structure formation in proteins. Classical models account for cooperative helix formation in terms of an energetically demanding nucleation event (described by the σ constant) followed by a more facile propagation reaction, with corresponding s constants that are sequence dependent. Extensive studies of folding and unfolding in model peptides have led to the determination of the propagation constants for amino acids. However, the role of individual side chains in helix nucleation has not been separately accessible, so the σ constant is treated as independent of sequence. We describe here a synthetic model that allows the assessment of th

SUBMITTER: Miller SE 

PROVIDER: S-EPMC4020114 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature