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Characterization of mutations that allow p-aminobenzoyl-glutamate utilization by Escherichia coli.
- Source :
-
Journal of bacteriology [J Bacteriol] 1998 Dec; Vol. 180 (23), pp. 6260-8. - Publication Year :
- 1998
-
Abstract
- An Escherichia coli strain deficient in p-aminobenzoate synthesis was mutagenized, and derivatives were selected for growth on folic acid. Supplementation was shown to be due to p-aminobenzoyl-glutamate present as a breakdown product in commercial folic acid preparations. Two classes of mutations characterized by the minimum concentration of p-aminobenzoyl-glutamate that could support growth were obtained. Both classes of mutations were genetically and physically mapped to about 30 min on the E. coli chromosome. A cloned wild-type gene from this region, abgT (formerly ydaH) could confer a similar p-aminobenzoyl-glutamate utilization phenotype on the parental strain. Interruption of abgT on the plasmid or on the chromosome of the mutant strain resulted in a loss of the phenotype. abgT was the third gene in an apparent operon containing abgA, abgB, abgT, and possibly ogt and might be regulated by a divergently transcribed LysR-type regulator encoded by abgR. Two different single-base-pair mutations that gave rise to the p-aminobenzoyl-glutamate utilization phenotype lay in the abgR-abgA intercistronic region and appeared to allow the expression of abgT. The second class of mutation was due to a tandem duplication of abgB and abgT fused to fnr. The abgA and abgB gene products were homologous to one another and to a family of aminoacyl aminohydrolases. p-Aminobenzoyl-glutamate hydrolysis could be detected in extracts from several of the mutant strains, but intact abgA and abgB were not essential for p-aminobenzoyl-glutamate utilization when abgT was supplied in trans.
- Subjects :
- Amino Acid Sequence
Base Sequence
Chromosome Mapping
Cloning, Molecular
DNA, Bacterial genetics
Dihydropteroate Synthase metabolism
Escherichia coli growth & development
Folic Acid metabolism
Gene Duplication
Hydrolysis
Molecular Sequence Data
Phenotype
Escherichia coli genetics
Escherichia coli metabolism
Genes, Bacterial
Glutamates metabolism
Mutation
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9193
- Volume :
- 180
- Issue :
- 23
- Database :
- MEDLINE
- Journal :
- Journal of bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 9829935
- Full Text :
- https://doi.org/10.1128/JB.180.23.6260-6268.1998