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J. Bacteriol., 01 1998, 128-135, Vol 180, No. 1
DR Macinga, GM Cook, RK Poole and PN Rather
Providencia stuartii contains a chromosomal 2'-N-acetyltransferase
[AAC(2')-Ia] involved in the O acetylation of peptidoglycan. The AAC(2')-Ia
enzyme is also capable of acetylating and inactivating certain
aminoglycosides and confers high-level resistance to these antibiotics when
overexpressed. We report the identification of a locus in P. stuartii,
designated aarF, that is required for the expression of AAC(2')-Ia.
Northern (RNA) analysis demonstrated that aac(2')-Ia mRNA levels were
dramatically decreased in a P. stuartii strain carrying an aarF::Cm
disruption. The aarF::Cm disruption also resulted in a deficiency in the
respiratory cofactor ubiquinone. The aarF locus encoded a protein that had
a predicted molecular mass of 62,559 Da and that exhibited extensive amino
acid similarity to the products of two adjacent open reading frames of
unknown function (YigQ and YigR), located at 86 min on the Escherichia coli
chromosome. An E. coli yigR::Kan mutant was also deficient in ubiquinone
content. Complementation studies demonstrated that the aarF and the E. coli
yigQR loci were functionally equivalent. The aarF or yigQR genes were
unable to complement ubiD and ubiE mutations that are also present at 86
min on the E. coli chromosome. This result indicates that aarF (yigQR)
represents a novel locus for ubiquinone production and reveals a previously
unreported connection between ubiquinone biosynthesis and the regulation of
gene expression.
Copyright © 1998, American Society for Microbiology
Identification and characterization of aarF, a locus required for production of ubiquinone in Providencia stuartii and Escherichia coli and for expression of 2'-N-acetyltransferase in P. stuartii [In Process Citation]
Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA.
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