Perturbation of Triple-Helix Structure in Mutant Collagens Examined by Subnanosecond Local Dynamics of Tryptophan: An Application of Time-Resolved Fluorescence Anisotropy

Abstract

Time-resolved fluorescence anisotropy can provide information about the local dynamic properties of a molecule at sub-nanometer resolution on the nano- and picosecond time scales. To help explain perturbations of the triple-helical structure of collagen induced by a mutation, and to facilitate an understanding of mutations associated with diseases like scurvy, an examination of synthetic collagen-like peptides was conducted. Results indicate that the extent of local motion increases near a mutation, demonstrating that the change in the amino acid interrupts the helical structure. Local motion, however, remains unchanged several amino acid residues away from the indole side chain of the tryptophan residue. In addition, the perturbation of the helical structure is asymmetric as there is an increase in the local motion of the indole side chain farther to the C-terminal side of the mutation.