Simulation study on the disordered state of an Alzheimer's beta amyloid peptide Abeta(12 36) in water consisting of random-structural, beta-structural, and helical clusters.

ABSTRACT: The monomeric Alzheimer's beta amyloid peptide, Abeta, is known to adopt a disordered state in water at room temperature, and a circular dichroism (CD) spectroscopy experiment has provided the secondary-structure contents for the disordered state: 70% random, 25% beta-structural, and 5% helical. We performed an enhanced conformational sampling (multicanonical molecular dynamics simulation) of a 25-residue segment (residues 12-36) of Abeta in explicit water and obtained the conformational ensemble over a wide temperature range. The secondary-structure contents calculated from the conformational ensemble at 300 degrees K reproduced the experimental secondary-structure contents. The constructed free-energy landscape at 300 degrees K was not plain but rugged with five clearly distinguishable c

SUBMITTER: Ikebe J 

PROVIDER: S-EPMC2203368 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature