Studies on the conformational transitions of rat skin collagen using a spin-label probe

Abstract

A technique is reported for spin labelling salt-soluble rat-skin collagen and using e.s.r. spectroscopy to study its conformational properties. The covalently labelled collagen undergoes a series of temperature-induced transitions which parallel those observed for native material. Three discrete processes are evident which are in accord with current view on the molecular unwinding of the tropocollagen triple helix into random coils. The temperature dependence of the e.s.r. spectra yields activation energies related to the expansion of the micro-environment around the probe. Evidence for the reversible destabilisation of spin-labelled tropocollagen by acetic acid, urea, and guanidine hydrochloride is presented.