The Conformation of N-Terminal Telopeptide of a, Chain from Rat Type I Collagen

Abstract

From type I collagen extracted from the lathyritic rat skin with a n eutral salt solution, α₁ theα1 polypeptide chain was separated on CM-cellulose column. The α₁, chain was cleaved by cyanogen bromide, and the peptide supposed to be corresponded to the a1-CB 1 peptide (N-ter minal telopeptide) was isolated. The isolated peptide was found to be incomplete as the α1-CB 1 peptide by amino acid analysis, but contained almost all sequences of N-termina l telopeptide. The obtained peptide was designated as α₁-CB 1'. The CD spectra in UV region revealed that 30% of the α₁-CB 1' peptide was the β-sheet structure and the remainder 70%the random coil state. By measurement of 11-I-NMR spectra in D20 in the temperature range of 5-50°C, the difference of 0.034 ppm for Tyr-α CH chemical shift and the difference of 0.022 ppm for Ala-α CH chemical shift were observed between 5 °C and 50 °C. The intensity of fluorescence of the peptide (excitation at 275 nm and emission at 305 nm) decreased as 34%, whenα1-CB 1' was mixed with CB 6. The intensity of fluorescence did not change, whenα₁-CB 1' was mixed with the CB 7. These results suggest the possibility that this α₁-C B 1'peptide interacts with the CB 6.