![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
Previous Article | Next Article 
Journal of Bacteriology, April 2000, p. 2018-2025, Vol. 182, No. 7
School of Biological Sciences, University of
Wales Bangor, Bangor, Gwynedd LL57 2UW, Wales, United Kingdom
Received 4 October 1999/Accepted 4 January 2000
A 5-kbp region upstream of the are-ben-cat genes was
cloned from Acinetobacter sp. strain ADP1, extending the
supraoperonic cluster of catabolic genes to 30 kbp. Four open reading
frames, salA, salR, salE, and
salD, were identified from the nucleotide sequence. Reverse
transcription-PCR studies suggested that these open reading frames are
organized into two convergent transcription units, salAR
and salDE. The salE gene, encoding a protein of
239 residues, was ligated into expression vector pET5a. Its product, SalE, was shown to have esterase activity against short-chain alkyl
esters of 4-nitrophenol but was also able to hydrolyze ethyl salicylate
to ethanol and salicylic acid. A mutant of ADP1 with a Kmr
cassette introduced into salE had lost the ability to
utilize only ethyl and methyl salicylates of the esters tested as sole carbon sources, and no esterase activity against ethyl salicylate could
be detected in cell extracts. SalE was induced during growth on ethyl
salicylate but not during growth on salicylate itself. salD
encoded a protein of undetermined function with homologies to the
Escherichia coli FadL membrane protein, which is involved in facilitating fatty acid transport, and a number of other proteins detected during aromatic catabolism, which may also function in hydrocarbon transport or uptake processes. A Kmr cassette
insertion in salD deleteriously affected cell growth and
viability. The salA and salR gene products
closely resemble two Pseudomonas proteins, NahG and NahR,
respectively encoding salicylate hydroxylase and the LysR family
regulator of both salicylate and naphthalene catabolism.
salA was cloned into pUC18 together with salR
and salE, and its gene product showed salicylate-inducible hydroxylase activity against a range of substituted salicylates, with
the same relative specific activities as found in wild-type ADP1 grown
on salicylate. Mutations involving insertion of Kmr
cassettes into salA and salR eliminated
expression of salicylate hydroxylase activity and the ability to grow
on either salicylate or ethyl salicylate. Studies of mutants with
disruptions of genes of the
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
sal Genes Determining the Catabolism of
Salicylate Esters Are Part of a Supraoperonic Cluster of Catabolic
Genes in Acinetobacter sp. Strain ADP1
-ketoadipate pathway with or without an
additional salE mutation confirmed that ethyl salicylate
and salicylate were channeled into the -ketoadipate pathway at the
level of catechol and thence dissimilated by the cat gene
products. SalR appeared to regulate expression of salA but
not salE.
*
Corresponding author. Mailing address: School of
Biological Sciences, University of Wales Bangor, Bangor, Gwynedd LL57
2UW, Wales, United Kingdom. Phone: (44) 1248 382363. Fax: (44) 1248 370731. E-mail: P.A.Williams{at}bangor.ac.uk.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |
