The stability of silk proteins to ultraviolet light is an issue of significant concern in both the appearance retention of silk-derived products and the preservation of historic silk textiles. Until now, evaluation of silk degradation has only been performed at the holistic, rather than molecular level. This paper describes the first proteomic profiling of silk photo-oxidation, characterising protein primary level modification leading to coloration changes, and evaluating the effects of tin weighting on photodegradation. Heavy chain fibroin, the main proteinaceous component of the silk thread, is a repetitive, highly crystalline protein with a content rich in tyrosine. Photoproducts of tyrosine were characterised and the levels of oxidative modification at the protein primary structural level correlated with changes in coloration and tensile strength. The effect of tin as a weighting agent used on historical fabrics was examined. Tin-weighted fabrics were evaluated following two treatments (pink and dynamite) and proteomic analysis revealed a significant increase in oxidatively modified amino acid residues within the pink treated silk. These findings offer significant new insight into the molecular-level oxidation of silk proteins under UV exposure, and the effects of silk treatments in either exacerbating or ameliorating this degradation.
|Number of pages||10|
|Journal||JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY|
|Publication status||In preparation - Sep 2012|
- Silk fibroin
- tin weighting
- historic textiles