Identification of mutations that alter the gating of the Escherichia coli mechanosensitive channel protein, MscK.

ABSTRACT: Mechanosensitive channels allow bacteria to survive rapid increases in turgor pressure. Substantial questions remain as to how these channels sense and respond to mechanical stress. Here we describe a set of mutants with alterations in their MscK channel protein. The mutants were detected fortuitously by their enhanced ability to modify the accumulation of quinolinic acid. Some amino acid changes lie in the putative pore region of MscK, but others affect sequences that lie amino-terminal to the domain aligning with MscS. We demonstrate that the alterations in MscK cause the channel to open more frequently in the absence of excessive mechanical stress. This is manifested in changes in sensitivity to external K(+) by cells expressing the mutant proteins. Single-channel analysis highlighted a

SUBMITTER: Li C 

PROVIDER: S-EPMC1890815 | biostudies-literature | 2007 Apr

REPOSITORIES: biostudies-literature