Molybdate-dependent transcription of hyc and nar operons of Escherichia coli requires MoeA protein and ModE-molybdate.
In Escherichia coli, ModE-molybdate, a repressor of modABCD operon (molybdate transport), was previously shown to be an additional transcriptional activator of hyc operon (formate hydrogenlyase) and narGHJI operon (respiratory nitrate reductase). However, in a modE mutant, both operons were expressed at about 50% of the wild-type level in a molybdate-dependent manner. This ModE-independent, molybdate-dependent, expression of hyc, narG and narK operons required MoeA protein. An E. coli modE, moeA double mutant failed to produce formate hydrogenlyase or respiratory nitrate reductase activity irrespective of the growth medium. Tungstate substituted for molybdate in the activation of transcription of hyc and nar operons by ModE could not replace molybdate for MoeA-dependent expression. It is proposed that the MoeA-catalyzed product, an activated form of molybdate, interacts with a transcriptional activator/regulator other than ModE and regulates hyc and nar operons.
Hasona
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Department of Microbiology and Cell Science, University of Florida, Gainesville 32611, USA.
Self
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Ray
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Shanmugam
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D001426:Bacterial Proteins; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins; D005560:Formate Dehydrogenases; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D006864:Hydrogenase; D008190:Lyases / Q000096:biosynthesis* / Q000235:genetics; D008982:Molybdenum / Q000378:metabolism*; D009097:Multienzyme Complexes; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000096:biosynthesis* / Q000235:genetics; D009566:Nitrates; D009876:Operon; D011993:Recombinant Fusion Proteins; D013466:Sulfurtransferases / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C491064:ModE protein, E coli; C101050:ModE protein, bacteria; D009097:Multienzyme Complexes; D009566:Nitrates; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C044659:molybdate; D008982:Molybdenum; D006864:Hydrogenase; D005560:Formate Dehydrogenases; C054017:formate hydrogenlyase; D009565:Nitrate Reductases; D050901:Nitrate Reductase; C111302:MoeA protein, E coli; D013466:Sulfurtransferases; D008190:Lyases