beta-sheet structure formation of proteins in solid state as revealed by circular dichroism spectroscopy

Cross beta -sheet structure formation and abnormal aggregation of proteins are thought to be pathological characteristics of some neurodegenerative di sorders. To investigate the novel structural transformation and aggregation , the solid-state secondary structures of some proteins and peptides associ ated in thin films were determined by circular dichroism spectroscopy. Insu lin, lysozyme, DsbA protein, luciferase, and ovalbumin peptide fall into on e group; they show no or slight structural rearrangement from solution to t he solid state. Another group, including bovine serum albumin, ovalbumin, a lpha -synuclein, and plasminogen activator inhibitor-1 (PAIRC) peptide, und ergo structural transformation with an increase of beta -sheet structure in the solid state. The beta -sheet formation of PAIRC peptide may reflect th e structural transformation of the serpin reactive center that is relevant to the inhibitor activity. The beta -sheet structure of alpha -synuclein in the solid state may correspond to the amyloid-like aggregates, which are i mplicated in the pathogenesis of some neurodegenerative diseases. (C) 2000 John Wiley & Sons, Inc.