期刊
JOURNAL OF BIOCHEMISTRY
卷 127, 期 5, 页码 931-937出版社
OXFORD UNIV PRESS
DOI: 10.1093/oxfordjournals.jbchem.a022689
关键词
ATP,Zn2+-dependent protease; chymotrypsin-like activity; FtsH; progressive degradation; unfolded structure
FtsH of Escherichia coli is an essential membrane-integrated ATP-dependent protease. We cloned a gene for an FtsH homolog (T.FtsH) from Thermus thermophilus HB8, expressed it in E. coli, and purified the expressed protein. ATPase activity of T.FtsH was activated by proteins with unfolded structure (alpha-casein and pepsin), and T.FtsH digested these proteins in an ATP-, Zn2+-dependent manner. alpha-Lactalbumin was digested by T.FtsH when it was largely unfolded, but not in its native form. Analysis of the proteolytic products revealed that, in most cases, T.FtsH cleaved the C-terminal side of hydrophobic residues and produced a characteristic set of small peptides (<30 kDa) without releasing a large intermediate. Thus, T.FtsH recognizes the unfolded structure of the proteins and progressively digests them at the expense of ATP. A soluble domain of T.FtsH, which lacked the N-terminal two transmembrane helices, was also prepared but was found to retain neither ATPase nor protease activities. Thus, the membrane segment appeared to be indispensable for these activities of T.FtsH.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据