Structural studies on fibrous biological material

This work is concerned with the structure, self-assembly and sequence of collagen. The complete amino acid sequence of the αl chain, as found in the collagen triple-helical molecular structure, is used in the following three ways. First, the electron microscopic, banding patterns, of the many ordered forms of intermolecular collagen assembly, are simulated on the basis of the known distribution of charged residues in the sequence (Chapters 2 and 3). In this way, various models, for the axially projected structures of these forms, are tested. The result is a set of experimentally determined intermolecular staggers or overlaps. Secondly, the distribution of residues along the sequence is analysed to find the origins of collagen self-assembly (Chapters 2 and 3). The specificity for each structure is due to the patterns of interacting residues along the sequence. Different residues, hence different distributions, seem to be important for each structure, depending on the physicochemical conditions of the mainly in vitro precipitations. Thirdly, the sequence is used to predict the meridional X-ray and neutron diffraction patterns from rat tail tendon (Chapter 4). There is substantial agreement with the observed patterns. This creates the possibility of interpreting the changes in meridional intensities, in terms of the sequence, from collagen fibrils in a variety of tissues and in many metabolic states.