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Mol Gen Genet. 1998 Jun;258(6):671-7.

Characterisation of the glnK-amtB operon and the involvement of AmtB in methylammonium uptake in Azorhizobium caulinodans.

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CNRS, URA 1300, D├ępartement des Biotechnologies, Institut Pasteur, Paris, France.


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.

[Indexed for MEDLINE]

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