Effect of monovalent anions on type I collagen fibrillogenesis in vitro

The effect of a set of monovalent anions with different preferential binding to proteins (C1-, Br-, I-, SCN-) on the kinetics of type I collagen fibrillogenesis was studied. Evidences obtained from turbidity-time curves and the Arrenhius plot suggested the presence of a conformational change prior to fibril formation, also supported by previous data available in the literature. A model of the initial steps of collagen assembly was proposed that could explain the action of the monovalent anions studied and other cosolvents on fibrillogenesis. Analysis of fibril width and 1-anilinonaphthalene-8-sulfonic acid (ANS) binding to collagen pointed to the presence of a nucleation process within the lag time.