Self assembly of mixtures of collagen alpha-chains

As part of an effort to understand the mechanism of assembly of collagen polypeptide chains into triple-helical rod shaped molecules, we have assessed the role of the proportions of alpha 1 to alpha 2 chains in the starting solutions in determining the compositions of renatured collagen. Solutions of different ratios of alpha 1 and alpha 2 chains, one of which was labelled with [14C]- or [3H]glycine, were renatured to form triple-helical, rod-shaped molecules, then cross-linked intramolecularly with formaldehyde. Specific radioactivity measurement and chromatographic elution profiles demonstrated that the composition of the resultant molecules, (alpha 1)3, (alpha 1)2 alpha 2, alpha 1(alpha 2)2 and (alpha 2)3, depended on a relative proportions of alpha chains in the starting solution.