Isolation and characterization of rcsB mutations that affect colanic acid capsule synthesis in Escherichia coli K-12

Geeta Gupte, Cora Woodward, Valerie Stout

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Regulation of colanic acid polysaccharide capsule synthesis in Escherichia coli requires the proteins RcsC and RcsB, in addition to several other proteins. By sequence similarity, these two proteins appear to be members of the two-component sensor-effector regulatory family found in bacteria. The present study characterizes the functional domains of RcsB. We have isolated mutations in rcsB that are able to suppress an rcsC 'up' mutation (i.e., leading to increase in cps transcription) that normally results in constitutive expression of the capsule. In addition, constitutive capsule mutations in rcsB have been isolated. From the characterization of the mutants and by analogy to the three-dimensional structure of CheY, we have begun to define different domains of RcsB and to assign functions to them. A few of the constitutive capsule mutations were localized in an acidic pocket that has been proposed to play a crucial role in phosphorylation of RcsB. As seen in other two-component systems, an aspartate-to-glutamate substitution at the presumed site of phosphorylation of RcsB resulted in constitutive capsule expression. Lastly, several of our rcsB mutants were found to be allele specific (rcsC137 specific) for rcsC, suggesting a physical as well as functional interaction between RcsC and RcsB proteins.

Original languageEnglish (US)
Pages (from-to)4328-4335
Number of pages8
JournalJournal of bacteriology
Volume179
Issue number13
DOIs
StatePublished - Jul 1997

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Fingerprint Dive into the research topics of 'Isolation and characterization of rcsB mutations that affect colanic acid capsule synthesis in Escherichia coli K-12'. Together they form a unique fingerprint.

Cite this