STRUCTURE OF BETA-KERATIN

The structure of β-keratin has been re-investigated. A trial structure obtained from energy calculations was refined on the basis of quantitative X-ray diffraction and infra-red data. If a crystal model with inter-sheet packing disorder similar to that present in the β-form of poly-L-alanine is assumed, the observed data can be satisfactorily accounted for by an antiparallel chain pleated sheet conformation. An alternative model with intra-sheet disorder was also considered. A Fourier synthesis using the observed hk0 intensities and calculated phases yielded an electron density map in which the main chain atoms were clearly resolved. © 1969.