期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2009
卷号：106
期号：32
页码：13272-13277
DOI：10.1073/pnas.0902651106
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：{alpha} -Crystallins are molecular chaperones that protect vertebrate eye lens proteins from detrimental protein aggregation. {alpha}B-Crystallin, 1 of the 2 {alpha}-crystallin isoforms, is also associated with myopathies and neuropathological diseases. Despite the importance of {alpha}-crystallins in protein homeostasis, only little is known about their quaternary structures because of their seemingly polydisperse nature. Here, we analyzed the structures of recombinant {alpha}-crystallins using biophysical methods. In contrast to previous reports, we show that {alpha}B-crystallin assembles into defined oligomers consisting of 24 subunits. The 3-dimensional (3D) reconstruction of {alpha}B-crystallin by electron microscopy reveals a sphere-like structure with large openings to the interior of the protein. {alpha}A-Crystallin forms, in addition to complexes of 24 subunits, also smaller oligomers and large clusters consisting of individual oligomers. This propensity might explain the previously reported polydisperse nature of {alpha}-crystallin.
关键词：electron microscopy ; molecular chaperone ; protein aggregation ; small heat shock protein ; stress response
