2D IR provides evidence for mobile water molecules in beta-amyloid fibrils.

ABSTRACT: The motion of water molecules close to amide groups causes their vibrational frequencies to vary rapidly in time. These variations are uniquely sensed by 2-dimensional infrared spectroscopy (2D IR). Here, it is proposed from 2-dimensional experiments on fibrils of amyloid beta (Abeta)40 that there are water molecules in the fibrils. The spatial locations of the water (D(2)O) were inferred from the responses of 18 amide modes of Abeta40 labeled with (13)C = (18)O. Fast frequency variations were found for residues L17 and V18 and for the apposed residues L34 and V36, suggesting cavities or channels containing mobile water molecules can form between the 2 sheets. Spectroscopic analysis showed that there are 1.2 water molecules per strand in the fibrils. The (13)C = (18)O substitution of 1 res

SUBMITTER: Kim YS 

PROVIDER: S-EPMC2764887 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature