Mass Spectrometric Analysis of UV-A Light-induced Cross-linking of the Lens Protein alphaB-crystallin with Antioxidant Supplementation.

摘要

UV-A light treatment introduces cross-links to the alphaB-crystallin and supplementation with various compounds alters this effect. (1) AA appears to limit UV-A induced cross-linking, but does not completely prevent it, while DHA increases cross-linking. (2) DTPA is essential in preventing high molecular weight aggregates, when supplementing samples with DHA. (3) Supplemented GSH appears to lessen DHA induced cross-linking, in both the presence and absence of DTPA. (4) When supplementing with GS, there were no observed differences between differing GS:protein ratios. Also, it appears that the presence of GS may increase cross-linking, with no apparent benefits from AA, DHA, or GSH. We have successfully fractionated the monomer and dimer species from UV-A induced samples using the GELFREE~(TM)8100 apparatus, allowing for a closer examination of each independently. Using tryptic digests, HPLC separation, and FT-ICR MS we have obtained 93.7percent sequence coverage of the monomer, and 84.6percent sequence coverage of the dimer. The exact nature of the cross-link(s) has yet to be defined.