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Uv damage of collagen: Insights from model collagen peptides
Author(s) -
Jariashvili Ketevan,
Madhan Balaraman,
Brodsky Barbara,
Kuchava Ana,
Namicheishvili Louisa,
Metreveli Nunu
Publication year - 2012
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.21725
Subject(s) - chemistry , circular dichroism , triple helix , collagen helix , peptide , cleavage (geology) , irradiation , type i collagen , biophysics , fibril , protein secondary structure , biochemistry , stereochemistry , biology , medicine , physics , geotechnical engineering , pathology , fracture (geology) , nuclear physics , engineering
Fibrils of Type I collagen in the skin are exposed to ultraviolet (UV) light and there have been claims that collagen photo‐degradation leads to wrinkles and may contribute to skin cancers. To understand the effects of UV radiation on collagen, Type I collagen solutions were exposed to the UV‐C wavelength of 254 nm for defined lengths of time at 4°C. Circular dichroism (CD) experiments show that irradiation of collagen leads to high loss of triple helical content with a new lower thermal stability peak and SDS‐gel electrophoresis indicates breakdown of collagen chains. To better define the effects of UV radiation on the collagen triple‐helix, the studies were extended to peptides which model the collagen sequence and conformation. CD studies showed irradiation for days led to lower magnitudes of the triple‐helix maximum at 225 nm and lower thermal stabilities for two peptides containing multiple Gly‐Pro‐Hyp triplets. In contrast, the highest radiation exposure led to little change in the T m values of (Gly‐Pro‐Pro) 10 and (Ala‐Hyp‐Gly) 10 , although (Gly‐Pro‐Pro) 10 did show a significant decrease in triple helix intensity. Mass spectroscopy indicated preferential cleavage sites within the peptides, and identification of some of the most susceptible sites of cleavage. The effect of radiation on these well defined peptides gives insight into the sequence and conformational specificity of photo‐degradation of collagen. © 2011 Wiley Periodicals, Inc. Biopolymers 97:189–198, 2012.