NR AOOK
AU McColl,I.H.; Blanch,E.W.; Gill,A.C.; Rhie,A.G.; Ritchie,M.A.; Hecht,L.; Nielsen,K.; Barron,L.D.
TI A new perspective on beta-sheet structures using vibrational Raman optical activity: from poly(L-lysine) to the prion protein.
QU Journal of the American Chemical Society 2003 Aug 20; 125(33): 10019-26
PT journal article
AB The vibrational Raman optical activity (ROA) spectrum of a polypeptide in a model beta-sheet conformation, that of poly(l-lysine), was measured for the first time, and the alpha-helix -> beta-sheet transition monitored as a function of temperature in H(2)O and D(2)O. Although no significant population of a disordered backbone state was detected at intermediate temperatures, some side chain bands not present in either the alpha-helix or beta-sheet state were observed. The observation of ROA bands in the extended amide III region assigned to beta-turns suggests that, under our experimental conditions, beta-sheet poly(L-lysine) contains up-and-down antiparallel beta-sheets based on the hairpin motif. The ROA spectrum of beta-sheet poly(L-lysine) was compared with ROA data on a number of native proteins containing different types of beta-sheet. Amide I and amide II ROA band patterns observed in beta-sheet poly(L-lysine) are different from those observed in typical beta-sheet proteins and may be characteristic of an extended flat multistranded beta-sheet, which is unlike the more irregular and twisted beta-sheet found in most proteins. However, a reduced isoform of the truncated ovine prion protein PrP(94-233) that is rich in beta-sheet shows amide I and amide II ROA bands similar to those of beta-sheet poly(L-lysine), which suggests that the C-terminal domain of the prion protein is able to support unusually flat beta-sheets. A principal component analysis (PCA) that identifies protein structural types from ROA band patterns provides a useful representation of the structural relationships among the polypeptide and protein states considered in the study.
MH Animal; Bacterial Outer Membrane Proteins/chemistry; Capsid Proteins/chemistry; Concanavalin A/chemistry; Levivirus; Polylysine/*chemistry; Prions/*chemistry; Protein Structure, Secondary; Sheep; Spectrum Analysis, Raman/*methods; Subtilisins/chemistry; Support, Non-U.S. Gov't; Virulence Factors, Bordetella/chemistry
AD Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K.
SP englisch
PO USA