Mutations in dsbA and dsbB, but not dsbC, lead to an enhanced sensitivity of Escherichia coli to Hg2+ and Cd2

• Published in: FEMS microbiology letters Vol. 174; no. 1; pp. 179 - 184
• Main Authors: Stafford, Simon J., Humphreys, David P., Lund, Peter A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.05.1999; Blackwell; Oxford University Press
• Subjects: Action of physical and chemical agents on bacteria; Bacteria; Bacterial Proteins - genetics; Bacteriology; Biological and medical sciences; Cadmium; Cadmium - pharmacology; Disulfide bond; Disulfide bonds; Drug Resistance, Microbial - genetics; dsb protein; DsbC gene; E coli; Escherichia coli - drug effects; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Gene expression; Genes; Gram-negative bacteria; Heavy metal toxicity; Isomerization; Membrane Proteins - genetics; Mercury; Mercury (metal); Mercury - pharmacology; Microbial Sensitivity Tests; Microbiology; Mutation; Periplasm; Protein Disulfide-Isomerases - genetics; Proteins; Salts; Sensitivity enhancement; Thiols; Disulfide bond; Heavy metal toxicity; protein; Resistance; Cadmium II; Toxicity; Escherichia coli; Mercury II; Bacteria; Protein; Enterobacteriaceae; Heavy metal
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.1999.tb13566.x

Abstract The Dsb proteins are involved in disulfide bond formation, reduction and isomerisation in a number of Gram-negative bacteria. Mutations in dsbA or dsbB, but not dsbC, increase the proportion of proteins with free thiols in the periplasm compared to wild-type. We investigated the effects of mutations in these genes on the bacterial resistance to mercuric and cadmium salts. Mutations in genes involved primarily in disulfide formation (dsbA and dsbB) generally enhanced the sensitivity to Hg2+ and Cd2+ while a mutation of the dsbC gene (primarily an isomerase of disulfide bonds) had no effect. Mutations of the dsb genes had no effect on the expression of the mercury-resistance determinants of the transposon Tn501.