Axially projected collagen structures

Abstract

The positively stained bands of the segment long spacing (s.l.s.) pattern of collagen are shown to be accounted for by the distribution of charged residues in the sequence of the $\alpha _{1}$ chain. The native tendon pattern can be constructed by repeated stagger of 234 residues between adjacent molecules, as in the Hodge-Petruska model. The relation of the precise version of this model to negatively stained patterns is shown and the part played by the teleopeptides revealed. A brief discussion of the meridional X-ray reflexions in terms of amino acid sequence is presented and related to electron microscope patterns. Optical diffraction suggests an approximate thirding of the D period. Finally a symmetric structure formed by reconstituting chick cartilage collagen is analysed and its origins revealed as an elaboration of the Hodge-Petruska model. It is shown to be related to the fibrous long spacing (f.l.s. I) structure.