Cloning and molecular characterization of the citrate utilizationcitMCDEFGRPcluster ofLeuconostoc paramesenteroides

Abstract

The citMCDEFGRP cluster from Leuconostoc paramesenteroides involved in citrate utilization was cloned and its nucleotide sequence determined. Homology of the inferred gene products with characterized enzymes reveals that citP encodes the citrate permease P, citC the citrate ligase and citDEF the subunits of the citrate lyase of Leuconostoc. Moreover, it suggests that citM encodes a Leuconostoc malic enzyme. Analysis of citrate consumption by and citrate lyase activity of Lc. paramesenteroides J1[pCITJ1] showed that its citrate permease and its citrate lyase are induced by the presence of citrate in the growth medium. Southern blot analysis demonstrated that the citMCDEFGRP cluster is located in a plasmid.

Citrate lyase CitE in Mycobacterium tuberculosis contributes to mycobacterial survival under hypoxic conditions

“…CitE has been confirmed as an ATP-independent citrate lyase in various other bacteria [30][31][32]. Unexpectedly, in the present study, we found that ATP inhibited the citrate cleavage activity of CitE.…”

“…Furthermore, we showed that MtbCitE was Mg 2+ dependent, and ATP could inhibit citrate cleavage activity. These findings indicated that the biochemical function of MtbCitE differed from that of other bacterial citrate lyases, including those from Escherichia coli [30], Klebsiella pneumoniae [31], and Leuconostoc paramesenteroides [32]. These previously described citrate lyase enzymes consist of an ATP-independent complex composed of six copies of each subunit, α, β, and γ.…”