Molecular cloning, nucleotide sequence, and promoter structure of the Acinetobacter calcoaceticus trpFB operon.
The trpFB operon from Acinetobacter calcoaceticus encoding the phosphoribosyl anthranilate isomerase and the beta-subunit of tryptophan synthase has been cloned by complementation of a trpB mutation in A. calcoaceticus, identified by deletion analysis, and sequenced. It encodes potential polypeptides of 214 amino acids with a calculated molecular weight of 23,008 (TrpF) and 403 amino acids with a molecular weight of 44,296 (TrpB). The encoded TrpB sequence shows striking homologies to those from other bacteria, ranging from 47% amino acids identity with the Brevibacterium lactofermentum protein and 64% identity with the Caulobacter crescentus protein. The encoded TrpF sequence, on the other hand, is much less homologous to the ones from other species, ranging between 27% identity with the Bacillus subtilis enzyme and 36% identity with the C. crescentus enzyme. The homologies of both polypeptides are evenly distributed over the entire sequences. The codon usage shows the strong preference for A and T in the third positions typical for A. calcoaceticus genes. The trpFB operon appears to be unlinked to trpA. The trpFB promoter has been determined by primer extension analysis of RNA synthesized from the chromosomally and plasmid-encoded trpFB operons. The starting nucleotides are identical in both cases and define the first promoter from A. calcoaceticus. Potential regulatory features are implied by a palindromic element overlapping the -35 consensus box of the promoter.
Lehrstuhl für Mikrobiologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Federal Republic of Germany.
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Kishan
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Hillen
D000150:Acinetobacter / Q000201:enzymology / Q000235:genetics*; D019747:Aldose-Ketose Isomerases; D000595:Amino Acid Sequence; D001483:Base Sequence; D002238:Carbohydrate Epimerases / Q000235:genetics*; D003001:Cloning, Molecular; D005816:Genetic Complementation Test; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D014367:Tryptophan Synthase / Q000235:genetics*
D046911:Macromolecular Substances; D014367:Tryptophan Synthase; D002238:Carbohydrate Epimerases; D019747:Aldose-Ketose Isomerases; C029865:phosphoribosylanthranilate isomerase