Probing polyproline structure and dynamics by photoinduced electron transfer provides evidence for deviations from a regular polyproline type II helix.

ABSTRACT: Polyprolines are well known for adopting a regular polyproline type II helix in aqueous solution, rendering them a popular standard as molecular ruler in structural molecular biology. However, single-molecule spectroscopy studies based on Förster resonance energy transfer (FRET) have revealed deviations of experimentally observed end-to-end distances of polyprolines from theoretical predictions, and it was proposed that the discrepancy resulted from dynamic flexibility of the polyproline helix. Here, we probe end-to-end distances and conformational dynamics of poly-l-prolines with 1-10 residues using fluorescence quenching by photoinduced-electron transfer (PET). A single fluorophore and a tryptophan residue, introduced at the termini of polyproline peptides, serve as sensitive probes for

SUBMITTER: Doose S 

PROVIDER: S-EPMC2077268 | biostudies-literature | 2007 Oct

REPOSITORIES: biostudies-literature