THE ROLE OF CYSTEINE RESIDUES IN THE TRANSPORT OF MERCURIC IONS BY THE TN501 MERT AND MERP MERCURY-RESISTANCE PROTEINS

被引:71
作者
MORBY, AP
HOBMAN, JL
BROWN, NL
机构
[1] Microbial Molecular Genetics and Cell Biology Group, School of Biological Sciences, University of Birmingham, Birmingham, B15 2TT, Edgbaston
关键词
D O I
10.1111/j.1365-2958.1995.mmi_17010025.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Each cysteine residue in the MerT and MerP polypeptides of bacterial transposon Tn501 was replaced by serine, and the mercury-resistance phenotypes of the mutants were determined in Escherichia coli. Cys-24 and Cys-25 in the first transmembrane region of MerT were essential for transport of mercuric ions through the cytoplasmic membrane, and mutations Cys-76-Ser, Cys-82-Ser or Gly-38-Asp in MerT or Cys-36-Ser in MerP all reduced transport and resistance. Deletion of the merP gene slightly reduced mercuric ion resistance and transport, whereas a Cys-33-Ser mutation in MerP appears to block transport of mercuric ions by MerT. The effects of deleting merP on mutations in merT were tested. The 116-amino-acid MerT protein is sufficient for mercuric ion transport across the cytoplasmic membrane.
引用
收藏
页码:25 / 35
页数:11
相关论文
共 53 条