The Rhizobium meliloti pmi gene encodes a new type of phosphomannose isomerase.
Interspecific complementation of a Xanthomonas campestris pv. campestris phosphomannose isomerase (PMI) mutant was used to isolate a cosmid from a genomic library of Rhizobium meliloti 2011 carrying the pmi gene of this strain. Subcloning experiments localized the coding region to a 2.0-kb SalI-ClaI fragment. Nucleotide sequence analysis of this fragment indicated the presence of two open reading frames (ORFs), coding for 18- and 43-kDa polypeptides. The analysis of the gene function by gene disruption experiments showed that ORF2 codes for pmi. A comparison of the deduced amino acid sequence with the corresponding sequences of the Pseudomonas aeruginosa and Escherichia coli PMIs revealed no significant homology, indicating that the isolated gene encodes a new type of PMI. The construction of a pmi-deficient mutant of R. meliloti using the sacB-sacR cassette technique showed that the loss of PMI activity does not affect the symbiotic properties of this strain.
Schmidt
M
M
Universität Bielefeld, Lehrstuhl für Genetik, Germany.
Arnold
W
W
Niemann
A
A
Kleickmann
A
A
Pühler
A
A
D000595:Amino Acid Sequence; D001483:Base Sequence; D004269:DNA, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008359:Mannose-6-Phosphate Isomerase / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames; D010957:Plasmids; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D016962:Sinorhizobium meliloti / Q000235:genetics*; D013728:Terminator Regions, Genetic; D016959:Xanthomonas campestris / Q000235:genetics
D004269:DNA, Bacterial; D008359:Mannose-6-Phosphate Isomerase