Quantum mechanical studies on model alpha-pleated sheets.

ABSTRACT: Pauling and Corey proposed a pleated-sheet configuration, now called alpha-sheet, as one of the protein secondary structures in addition to alpha-helix and beta-sheet. Recently, it has been suggested that alpha-sheet is a common feature of amyloidogenic intermediates. We have investigated the stability of antiparallel beta-sheet and two conformations of alpha-sheet in solution phase using the density functional theoretical method. The peptides are modeled as two-strand acetyl-(Ala)(2)-N-methylamine. Using stages of geometry optimization and single point energy calculation at B3LYP/cc-pVTZ//B3LYP/6-31G* level and including zero-point energies, thermal, and entropic contribution, we have found that beta-sheet is the most stable conformation, while the alpha-sheet proposed by Pauling and Core

SUBMITTER: Wu H 

PROVIDER: S-EPMC2841717 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature