Catabolite repression of the citrate fermentation genes in Klebsiella pneumoniae: evidence for involvement of the cyclic AMP receptor protein.

ABSTRACT: Klebsiella pneumoniae is able to grow anaerobically with citrate as a sole carbon and energy source by a fermentative pathway involving the Na(+)-dependent citrate carrier CitS, citrate lyase, and oxaloacetate decarboxylase. The corresponding genes are organized in the divergent citC and citS operons, whose expression is strictly dependent on the citrate-sensing CitA-CitB two-component system. Evidence is provided here that the citrate fermentation genes are subject to catabolite repression, since anaerobic cultivation with a mixture of citrate and glucose or citrate and gluconate resulted in diauxic growth. Glucose, gluconate, and also glycerol decreased the expression of a chromosomal citS-lacZ fusion by 60 to 75%, whereas a direct inhibition of the citrate fermentation enzymes was not o

SUBMITTER: Meyer M 

PROVIDER: S-EPMC95405 | biostudies-literature | 2001 Sep

REPOSITORIES: biostudies-literature