|
|
||||||||
Genetics and Molecular Biology |
Department of Biology, Dalhousie University, Halifax, Nova Scotia, CanadaB3H 4J11
Author for correspondence: L. C. Vining. Tel: +1 902 494 2040. Fax: +1 902 494 3736. e-mail: Leo.Vining{at}Dal.Ca
Regions of the Streptomyces venezuelae ISP5230 chromosome flanking pabAB, an amino-deoxychorismate synthase gene needed for chloramphenicol (Cm) production, were examined for involvement in biosynthesis of the antibiotic. Three of four ORFs in the sequence downstream of pabAB resembled genes involved in the shikimate pathway. BLASTX searches of GenBank showed that the deduced amino acid sequences of ORF3 and ORF4 were similar to proteins encoded by monofunctional genes for chorismate mutase and prephenate dehydrogenase, respectively, while the sequence of the ORF5 product resembled deoxy-arabino-heptulosonate-7-phosphate (DAHP) synthase, the enzyme that initiates the shikimate pathway. A relationship to Cm biosynthesis was indicated by sequence similarities between the ORF6 product and membrane proteins associated with Cm export. BLASTX searches of GenBank for matches with the translated sequence of ORF1 in chromosomal DNA immediately upstream of pabAB did not detect products relevant to Cm biosynthesis. However, the presence of Cm biosynthesis genes in a 7·5 kb segment of the chromosome beyond ORF1 was inferred when conjugal transfer of the DNA into a blocked S. venezuelae mutant restored Cm production. Deletions in the 7·5 kb segment of the wild-type chromosome eliminated Cm production, confirming the presence of Cm biosynthesis genes in this region. Sequencing and analysis located five ORFs, one of which (ORF8) was deduced from BLAST searches of GenBank, and from characteristic motifs detected in alignments of its deduced amino acid sequence, to be a monomodular nonribosomal peptide synthetase. GenBank searches did not identify ORF7, but matched the translated sequences of ORFs 9, 10 and 11 with short-chain ketoreductases, the ATP-binding cassettes of ABC transporters, and coenzyme A ligases, respectively. As has been shown for ORF2, disrupting ORF3, ORF7, ORF8 or ORF9 blocked Cm production.
Keywords: p-aminophenylalanine, gene disruption, mutant complementation, sequence analysis
Abbreviations: ADC, 4-amino-4-deoxychorismate; Am, apramycin; Cm, chloramphenicol; DAHP, deoxy-arabino-heptulosonate-7-phosphate; Km, kanamycin; NRPS, non-ribosomal peptide synthetase; PABA, p-aminobenzoic acid; PAPA, p-aminophenylalanine; PAPS, p-aminophenylserine; Ts, thiostrepton
The GenBank accession number for the sequence reported in this paper is AF262220.
a Present address: Shenyang Pharmaceutical University, Shenyang, P.R. China.
b Present address: Department of Natural Products Microbiology, Wyeth Ayerst Research, 401 N. Middletown Rd, Pearl River, NY 10965, USA.
This article has been cited by other articles:
![]() |
T. Nishizawa, C. C. Aldrich, and D. H. Sherman Molecular Analysis of the Rebeccamycin L-Amino Acid Oxidase from Lechevalieria aerocolonigenes ATCC 39243 J. Bacteriol., March 15, 2005; 187(6): 2084 - 2092. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. E. Jensen, A. S. Paradkar, R. H. Mosher, C. Anders, P. H. Beatty, M. J. Brumlik, A. Griffin, and B. Barton Five Additional Genes Are Involved in Clavulanic Acid Biosynthesis in Streptomyces clavuligerus Antimicrob. Agents Chemother., January 1, 2004; 48(1): 192 - 202. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Piraee, R. L. White, and L. C. Vining Biosynthesis of the dichloroacetyl component of chloramphenicol in Streptomyces venezuelae ISP5230: genes required for halogenation Microbiology, January 1, 2004; 150(1): 85 - 94. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Kloosterman, G. I. Hessels, J. W. Vrijbloed, G. J. Euverink, and L. Dijkhuizen (De)regulation of key enzyme steps in the shikimate pathway and phenylalanine-specific pathway of the actinomycete Amycolatopsis methanolica Microbiology, November 1, 2003; 149(11): 3321 - 3330. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Wang and L. C. Vining Control of growth, secondary metabolism and sporulation in Streptomyces venezuelae ISP5230 by jadW1, a member of the afsA family of {gamma}-butyrolactone regulatory genes Microbiology, August 1, 2003; 149(8): 1991 - 2004. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Chang and L. C. Vining Biosynthesis of sulfur-containing amino acids in Streptomyces venezuelae ISP5230: roles for cystathionine {beta}-synthase and transsulfuration Microbiology, July 1, 2002; 148(7): 2135 - 2147. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Pootoolal, M. G. Thomas, C. G. Marshall, J. M. Neu, B. K. Hubbard, C. T. Walsh, and G. D. Wright Assembling the glycopeptide antibiotic scaffold: The biosynthesis of A47934 from Streptomyces toyocaensis NRRL15009 PNAS, June 25, 2002; 99(13): 8962 - 8967. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Wang, R. L. White, and L. C. Vining Biosynthesis of the dideoxysugar component of jadomycin B: genes in the jad cluster of Streptomyces venezuelae ISP5230 for L-digitoxose assembly and transfer to the angucycline aglycone Microbiology, April 1, 2002; 148(4): 1091 - 1103. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |