Meridional Reflexions in the X-ray Diffraction Photographs of α-Keratin

Abstract

X-RAY diffraction photographs of various keratins taken with fine-slit collimators of high resolution display a rich series of meridional reflexions^1–3. Their spacings may conveniently be regarded as orders of a macro-period of 198 A. with very few exceptions. Astbury⁴ has used the spacings and intensities of reflexions reported by Bear and others, from porcupine quill tip, to derive a one-dimensional Patterson diagram, and to explore the possibility of finding the sequence of amino-acid residues in the protein chains of the crystalline portion of the keratin. It might well be that the differences among keratins could provide useful clues in this quest, and the present intention is to direct attention to them.