Sodium Dodecyl Sulfate Hypersensitivity of clpP and clpB Mutants of Escherichia coli

Authors

Soumitra Rajagopal, University of Nebraska-Lincoln
Narasimhan Sudarsan, University of Nebraska-Lincoln
Kenneth W. Nickerson, University of Nebraska-LincolnFollow

Date of this Version

August 2002

Comments

Published in APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Aug. 2002, p. 4117–4121 Vol. 68, No. 8. Copyright © 2002, American Society for Microbiology. Used by permission.

Abstract

We studied the hypersensitivity of clpP and clpB mutants of Escherichia coli to sodium dodecyl sulfate (SDS). Both wild-type E. coli MC4100 and lon mutants grew in the presence of 10% SDS, whereas isogenic clpP and clpB single mutants could not grow above 0.5% SDS and clpA and clpX single mutants could not grow above 5.0% SDS. For wild-type E. coli, cellular ClpP levels as determined by Western immunoblot analysis increased ca. sixfold as the levels of added SDS increased from 0 to 2%. Capsular colanic acid, measured as uronic acid, increased ca. sixfold as the levels of added SDS increased from 2 to 10%. Based on these findings, 3 of the 19 previously identified SDS shock proteins (M. Adamowicz, P. M. Kelley, and K. W. Nickerson, J. Bacteriol. 173:229-233, 1991) are tentatively identified as ClpP, ClpX, and ClpB.