Abstract

A gene encoding lysine 6-aminotransferase, which forms the beta-lactam precursor alpha-aminoadipic acid, is located in the cluster of cephamycin biosynthetic genes in Nocardia lactamdurans. J J Coque , P Liras , L Laiz and J F Martín Department of Ecology, Genetics and Microbiology, Faculty of Biology, University of León, Spain. ABSTRACT A gene (lat) encoding lysine 6-aminotransferase was found upstream of the pcbAB (encoding alpha-aminoadipylcysteinyl-valine synthetase) and pcbC (encoding isopenicillin N synthase) genes in the cluster of early cephamycin biosynthetic genes in Nocardia lactamdurans. The lat gene was separated by a small intergenic region of 64 bp from the 5' end of the pcbAB gene. The lat gene contained an open reading frame of 1,353 nucleotides (71.4% G + C) encoding a protein of 450 amino acids with a deduced molecular mass of 48,811 Da. Expression of DNA fragments carrying the lat gene in Streptomyces lividans led to a high lysine 6-aminotransferase activity which was absent from untransformed S. lividans. The enzyme was partially purified from S. lividans(pULBS8) and showed a molecular mass of 52,800 Da as calculated by Sephadex gel filtration and polyacrylamide gel electrophoresis. DNA sequences which hybridized strongly with the lat gene of N. lactamdurans were found in four cephamycin-producing Streptomyces species but not in four other actinomycetes which are not known to produce beta-lactams, suggesting that the gene is specific for beta-lactam biosynthesis and is not involved in general lysine catabolism. The protein encoded by the lat gene showed similarity to ornithine-5-aminotransferases and N-acetylornithine-5-aminotransferases and contained a pyridoxal phosphate-binding consensus amino acid sequence around Lys-300 of the protein. The evolutionary implications of the lat gene as a true beta-lactam biosynthetic gene are discussed. CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? « Previous | Next Article » Table of Contents This Article J. Bacteriol. October 1991 vol. 173 no. 19 6258-6264 » Abstract PDF Classifications Research Article Services Email this article to a colleague Similar articles in ASM journals Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of JB Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Load citing article information Citing articles via Web of Science Citing articles via Google Scholar Google Scholar Articles by Coque, J. J. Articles by Martín, J. F. Search for related content PubMed PubMed citation Articles by Coque, J. J. Articles by Martín, J. F. Related Content Load related web page information Social Bookmarking CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? current issue December 2011, volume 193, issue 24 Alert me to new issues of JB About JB Subscribers Authors Reviewers Advertisers Inquiries from the Press Permissions & Commercial Reprints ASM Journals Public Access Policy JB RSS Feeds 1752 N Street N.W. • Washington DC 20036 202.737.3600 • 202.942.9355 fax • journals@asmusa.org Print ISSN: 0021-9193 Online ISSN: 1098-5530 Copyright © 2011 by the American Society for Microbiology. For an alternate route to JB .asm.org, visit: http://intl- JB .asm.org | More Info» var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); var pageTracker = _gat._getTracker("UA-5821458-9"); pageTracker._trackPageview();