An essential amino acid residue in the protein translocation channel revealed by targeted random mutagenesis of SecY
Abstract
The SecY/Sec61α family of membrane proteins are the central subunits of the putative protein translocation channel. We introduced random mutations into a segment of Escherichia coli SecY within its cytoplasmic domain 5, which was shown previously to be important for the SecA-dependent translocation activity. Mutations were classified into those retaining function and those gaining a dominant-interfering ability caused by a loss of function. These analyses showed that Arg-357, Pro-358, Gly-359, and Thr-362 are functionally important; Arg-357, conserved in almost all organisms, was identified as an indispensable residue.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- April 2001
- DOI:
- 10.1073/pnas.081617398
- Bibcode:
- 2001PNAS...98.5128M
- Keywords:
-
- Genetics