Characterisation of the glnK-amtB operon and the involvement of AmtB in methylammonium uptake in Azorhizobium caulinodans.
This work reports the characterisation of the Azorhizobium caulinodans amtB gene, the deduced protein sequence of which shares similarity to those of several ammonium transporters. amtB is located downstream from glnK, a glnB-like gene. It is cotranscribed with glnK from an NtrC- and sigma54-dependent promoter. glnK and amtB insertion mutant strains have been isolated. Methylammonium uptake was assayed in these strains and in other mutant strains in which the regulation of nitrogen metabolism is impaired. Our data suggest that the AmtB protein is an ammonium transporter, which is mainly regulated by NtrC in response to nitrogen availability.
Michel-Reydellet
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CNRS, URA 1300, Département des Biotechnologies, Institut Pasteur, Paris, France. nreydel@pasteur.fr
Desnoues
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de Zamaroczy
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Elmerich
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Kaminski
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PA
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D029968:Escherichia coli Proteins; D017136:Ion Transport; D008744:Methylamines / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009713:Nucleotidyltransferases; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics*; D051922:PII Nitrogen Regulatory Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D051877:RNA Polymerase Sigma 54; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D015183:Restriction Mapping; D012230:Rhizobiaceae / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000235:genetics; D015534:Trans-Activators; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000235:genetics
C111096:AmtB protein, E coli; D001426:Bacterial Proteins; D002352:Carrier Proteins; D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C113488:GlnK protein, Azorhizobium caulinodans; D008744:Methylamines; D051922:PII Nitrogen Regulatory Proteins; D000644:Quaternary Ammonium Compounds; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012808:Sigma Factor; D015534:Trans-Activators; D014157:Transcription Factors; C497876:glnG protein, E coli; C497751:rpoN protein, E coli; C027451:methylamine; C497878:glnK protein, E coli; D009713:Nucleotidyltransferases; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54