title: Amyloid beta-protein: experiment and theory on the 21-30 fragment.
abstract: The structure of the 21-30 fragment of the amyloid beta-protein (Abeta) was investigated by ion mobility mass spectrometry and replica exchange dynamics simulations. Mutations associated with familial Alzheimer's disease (E22G, E22Q, E22K, and D23N) of Abeta(21-30) were also studied, in order to understand any structural changes that might occur with these substitutions. The structure of the WT peptide shows a bend and a perpendicular turn in the backbone which is maintained by a network of D23 hydrogen bonding. Results for the mutants show that substitutions at E22 do little to alter the overall structure of the fragment. A substitution at D23 resulted in a change of structure for Abeta(21-30). A comparison of these gas-phase studies to previous solution-phase studies reveals that the peptide can fold in the absence of solvent to a structure also seen in solution, highlighting the important role of the D23 hydrogen bonding network in stabilizing the fragment's folded structure.
authors.affiliation: Department of Chemistry, University of California, Santa Barbara, California 93106, USA.
authors.forename: Megan M
authors.initials: MM
authors.lastname: Murray
authors.forename: Mary Griffin
authors.initials: MG
authors.lastname: Krone
authors.forename: Summer L
authors.initials: SL
authors.lastname: Bernstein
authors.forename: Andrij
authors.initials: A
authors.lastname: Baumketner
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Condron
authors.forename: Noel D
authors.initials: ND
authors.lastname: Lazo
authors.forename: David B
authors.initials: DB
authors.lastname: Teplow
authors.forename: Thomas
authors.initials: T
authors.lastname: Wyttenbach
authors.forename: Joan-Emma
authors.initials: JE
authors.lastname: Shea
authors.forename: Michael T
authors.initials: MT
authors.lastname: Bowers