Conversion of yeast phosphoglycerate kinase into amyloid-like structure

Yeast phosphoglycerate kinase is a structurally well-characterized enzyme c onsisting of 415 amino acids without disulfide bonds. Anion-induced refoldi ng from its acid-unfolded state gives rise to the formation of worm-like am yloid fibrils with a persistence length of 73 nm, Electron microscopy and s mall-angle X-ray scattering data indicate that the fibrils have an elliptic al cross-section with dimensions of 10.2 nm x 5.1 nm, About half of all ami no acids are organized in form of cross-beta structure which gives rise to typical infrared spectra, X-ray diffraction and yellow-green birefringence after Congo red staining. The kinetics of amyloid formation, monitored by i nfrared spectroscopy, dynamic light scattering and X-ray scattering, was fo und to be strongly dependent on protein concentration The infrared data ind icate that the formation of cross-beta structure practically comes to an en d already after some hours, whereas the length-growth of the amyloid fibril s, monitored by small-angle X-ray scattering was not yet completed after 1, 300 hours. (C) 2000 Wiley-Liss, Inc.