Studies on collagen. II. Cylindrical lattice structure of collagen

Abstract

It is suggested that the structure of collagen is based on a cylindrical lattice. The protofibrils, consisting of triple chains, are packed together in a hexagonal array close to the centre, and are extended outwards in the form of cylindrical sheets. Each sheet has a pseudohexagonal symmetry about the common axis. This cylindrical lattice explains (a) the large number of equatorial reflections of long spacing observed in the diffraction pattern of native fibres and (b) the absence of the 110 reflection and its analogue in all layer lines. The number of sheets in a single cylindrical rod is about 7 and its diameter about 200 Å. The above results were verified by model optical diffraction experiments. Also, from these experiments it is shown that the structure can also belong to the roll type with the added advantage that the formation of a roll in the form of a continuous sheet is more probable from the point of view of fibrogenesis.