Recognition and binding of a helix-loop-helix peptide to carbonic anhydrase occurs via partly folded intermediate structures.

ABSTRACT: We have studied the association of a helix-loop-helix peptide scaffold carrying a benzenesulfonamide ligand to carbonic anhydrase using steady-state and time-resolved fluorescence spectroscopy. The helix-loop-helix peptide, developed for biosensing applications, is labeled with the fluorescent probe dansyl, which serves as a polarity-sensitive reporter of the binding event. Using maximum entropy analysis of the fluorescence lifetime of dansyl at 1:1 stoichiometry reveals three characteristic fluorescence lifetime groups, interpreted as differently interacting peptide/protein structures. We characterize these peptide/protein complexes as mostly bound but unfolded, bound and partly folded, and strongly bound and folded. Furthermore, analysis of the fluorescence anisotropy decay resulted in t

SUBMITTER: Lignell M 

PROVIDER: S-EPMC2814212 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature