JB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Hussein, M. J.
Right arrow Articles by Nichols, B. P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Hussein, M. J.
Right arrow Articles by Nichols, B. P.

 Previous Article  |  Next Article 

Journal of Bacteriology, December 1998, p. 6260-6268, Vol. 180, No. 23
0021-9193/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Characterization of Mutations That Allow p-Aminobenzoyl-Glutamate Utilization by Escherichia coli

Mouyassar J. Hussein,1 Jacalyn M. Green,2 and Brian P. Nichols1,*

Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607,1 and Department of Basic Biomedical Sciences, Dr. William M. Scholl College of Podiatric Medicine, Chicago, Illinois 606122

Received 13 May 1998/Accepted 23 September 1998

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.

* Corresponding author. Mailing address: Laboratory for Molecular Biology, Department of Biological Sciences, Molecular Biology Research Building m/c 567, University of Illinois at Chicago, 900 S. Ashland Ave., Chicago, IL 60607. Phone: (312) 996-5064. Fax: (312) 413-2691. E-mail: brian.p.nichols{at}uic.edu.

Journal of Bacteriology, December 1998, p. 6260-6268, Vol. 180, No. 23
0021-9193/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 1998 by the American Society for Microbiology. All rights reserved.