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Indexed by:期刊论文

Date of Publication:2013-01-04

Journal:JOURNAL OF BIOLOGICAL CHEMISTRY

Included Journals:SCIE、EI、PubMed、Scopus

Volume:288

Issue:1

Page Number:99-109

ISSN No.:0021-9258

Abstract:Some mutants of human gamma D-crystallin are closely linked to congenital cataracts, although the detailed molecular mechanisms of mutant-associated cataract formation are generally not known. Here we report on a recently discovered gamma D-crystallin mutant (W42R) that has been linked to autosomal dominant, congenital cataracts in a Chinese family. The mutant protein is much less soluble and stable than wild-type gamma D-crystallin. We solved the crystal structure of W42R at 1.7 angstrom resolution, which revealed only minor differences from the wild-type structure. Interestingly, the W42R variant is highly susceptible to protease digestion, suggesting the presence of a small population of partially unfolded protein. This partially unfolded species was confirmed and quantified by NMR spectroscopy. Hydrogen/deuterium exchange experiments revealed chemical exchange between the folded and unfolded species. Exposure of wild-type gamma D-crystallin to UV caused damage to the N-terminal domain of the protein, resulting in very similar proteolytic susceptibility as observed for the W42R mutant. Altogether, our combined data allowed us to propose a model for W42R pathogenesis, with the W42R mutant serving as a mimic for photodamaged gamma D-crystallin involved in age-related cataract.