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Polypeptide models of collagen: Properties of (Pro‐Pro‐βAla) n
Author(s) -
Bhatnagar Rajendra S.,
Rapaka Rao S.
Publication year - 1975
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1975.360140313
Subject(s) - chemistry , optical rotation , circular dichroism , optical rotatory dispersion , cotton effect , triple helix , crystallography , glycine , dispersion (optics) , stereochemistry , amino acid , optics , biochemistry , organic chemistry , physics
We have synthesized (Pro‐Pro‐βAla) n as a model for collagen. The synthetic polytripeptide, mol wt 6500, exhibits a large negative optical rotation with a very strong negative Cotton effect centered at 216 nm. The optical rotatory dispersion of (Pro‐Pro‐βAla) n followed a single‐term Drude equation and the λ c was 195 nm. The rotation decreased markedly on heating with the midpoint of the broad transition at 55°C. Preliminary studies also showed loss of structure in guadinine HCl. The circular dichroism spectrum of the polymer exhibited a deep trough at 190 nm. The marked similarities of solution properties of (Pro‐Pro‐βAla) n to (Pro‐Pro‐Gly) n suggest that β‐alanine can replace glycine in generating collagen‐like helix in solution.