Characterizing aqueous solution conformations of a peptide backbone using Raman optical activity computations.

ABSTRACT: Mounting spectroscopic evidence indicates that alanine predominantly adopts extended polyproline II (PPII) conformations in short polypeptides. Here we analyze Raman optical activity (ROA) spectra of N-acetylalanine-N'-methylamide (Ala dipeptide) in H2O and D2O using density functional theory on Monte Carlo (MC) sampled geometries to examine the propensity of Ala dipeptide to adopt compact right-handed (alpha(R)) and left-handed (alpha(L)) helical conformations. The computed ROA spectra based on MC-sampled alpha(R) and PPII peptide conformations contain all the key spectral features found in the measured spectra. However, there is no significant similarity between the measured and computed ROA spectra based on the alpha(L)- and beta-conformations sampled by the MC methods. This analysis su

SUBMITTER: Mukhopadhyay P 

PROVIDER: S-EPMC2599840 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature