期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 279, 期 2, 页码 901-909出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M308296200
关键词
-
资金
- NIGMS NIH HHS [GM34766] Funding Source: Medline
CvaB, a member of the ATP-binding cassette transporter superfamily, is the central membrane transporter of the colicin V secretion system in Escherichia coli. Cys(32) and His(105) in the N-terminal domain of CvaB were identified as critical residues for both colicin V secretion and cysteine proteolytic activity. By inhibiting degradation with N-ethylmaleimide and a mixture of protease inhibitors, a stable wild-type N-terminal domain (which showed cysteine protease activity when activated) was purified. Such protease activity was Ca2+- and concentration-dependent and could be inhibited by antipain, N-ethylmaleimide, EDTA, and EGTA. At low concentrations, the Ca2+ analogs Tb3+ and La3+ (but not Fe3+) significantly enhanced proteolytic activity, suggesting that the size of the cations is important for activity. Together with comparisons of the sequences of members of the cysteine protease family, these results indicate that Cys(32) and His(105) are the critical residues in the CvaB N-terminal domain for the calcium-dependent cysteine protease activity and secretion of colicin V.
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