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论文类型：期刊论文

发表时间：2013-01-04

发表刊物：JOURNAL OF BIOLOGICAL CHEMISTRY

收录刊物：SCIE、EI、PubMed、Scopus

卷号：288

期号：1

页面范围：99-109

ISSN号：0021-9258

摘要：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.