Book of Abstracts: Albany 2007
June 19-23 2007
Beta-Sheet Folding and Fibrillation of 11-kDa Polypeptide is Completely Aggregation Driven
A de novo 140-amino acid residue polypeptide YE8 with a regular 16 amino acid repeat sequence, (GA)3GY(GA)3GE exhibits remarkable folding properties and, as well, forms fibrillar structures. Deep UV Resonance Raman spectroscopy was employed to investigate the polypeptide structural transformations during the folding and fibrillation process. We found that the YE8 polypeptide shows all the properties of a typical amyloid fibril-forming protein including a pronounced directing or templating effect. A strong concentration dependence for β-sheet formation correlates with the lag time. However, despite the ability of the repetitive unit GAGAGAG to form a highly regular β-sheet structure, there was no evidence for intramolecular promotion of folding by the YE8 polypeptide. AFM, TEM, CD, and fluorescence spectroscopy were also used in this work.
Natalya I. Topilina*
University at Albany