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：2008
卷号：105
期号：36
页码：13379-13384
DOI：10.1073/pnas.0805689105
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Coupling factor B (FB) is a mitochondrial inner membrane polypeptide that facilitates the energy-driven catalysis of ATP synthesis in animal mitochondria by blocking a proton leak across the membrane. Here, we report the crystal structure of the bovine mitochondrial FB mutant with Gly-3-Glu substitution determined at a resolution of 0.96 A and that of the WT polypeptide at a resolution of 2.9 A. The structure reveals an oblong, oval-shaped molecule with a unique globular N-terminal domain that is proposed to be the membrane anchor domain and the capping region to the C-terminal leucine-rich repeats domain. A short N-terminal {alpha}-helix, which extends away from the molecule's body, is suggestive of functioning as an anchor for FB to the matrix side of the mitochondrial inner membrane. Identification of a bound Mg2+ ion reveals that FB is a metalloprotein. We also report the cocrystal structures of FB bound with phenylarsine oxide and Cd2+, two known inhibitors of the FB coupling activity.
