Using D-Amino Acids to Delineate the Mechanism of Protein Folding: Application to Trp-cage.

ABSTRACT: Using the miniprotein Trp-cage as a model, we show that D-amino acids can be used to facilitate the delineation of protein folding mechanism. Specifically, we study the folding-unfolding kinetics of three Trp-cage mutants where the native glycine residue near the C-terminus of the α-helix is replaced by a D-amino acid. A previous study showed that these mutations increase the Trp-cage stability, due to a terminal capping effect. Our results show that the stabilizing effect of D-asparagine and D-glutamine originates almost exclusively from a decrease in the unfolding rate, while the D-alanine mutation results in a similar decrease in the unfolding rate, but it also increases the folding rate. Together, these results support a folding mechanism wherein the α-helix formation in the transition

SUBMITTER: Culik RM 

PROVIDER: S-EPMC3844134 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature