960 13 4129 3 11514 document 4129 22002434 application/xml c324b6aef8bba1929f71dc042d9bf0e6 MD5 89595 2014-02-11 07:22:38 http://eprints.iliauni.edu.ge/960/1/22002434 960 1 1 application/xml text en public

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published archive 105 disk0/00/00/09/60 2014-02-11 08:32:26 2014-02-11 08:32:26 2014-02-11 08:32:26 article show Metreveli Nunu nunu_metreveli@iliauni.edu.ge Jariashvili Ketevan MadhanI Balaraman Brodsky Barbara Kuchava Ana Namicheishvili Louisa pub QC QH301 ins14 public 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 Tm 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. 2012-03 published Biopolymers 97 3 189-198 10.1002/bip.21725 TRUE