HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Eustáquio, A. S. Articles by Heide, L. Search for Related Content PubMed PubMed Citation Articles by Eustáquio, A. S. Articles by Heide, L. Agricola Articles by Eustáquio, A. S. Articles by Heide, L.

NovG, a DNA-binding protein acting as a positive regulator of novobiocin biosynthesis

¹ Pharmazeutische Biologie, Pharmazeutisches Institut, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany

Correspondence
Lutz Heide
heide{at}uni-tuebingen.de

The biosynthetic gene cluster of the aminocoumarin antibiotic novobiocin contains two putative regulatory genes, i.e. novE and novG. The predicted gene product of novG shows a putative helix–turn–helix DNA-binding motif and shares sequence similarity with StrR, a well-studied pathway-specific transcriptional activator of streptomycin biosynthesis. Here functional proof is provided, by genetic and biochemical approaches, for the role of NovG as a positive regulator of novobiocin biosynthesis. The entire novobiocin cluster of the producer organism Streptomyces spheroides was expressed in the heterologous host Streptomyces coelicolor M512, and additional strains were produced which lacked the novG gene within the heterologously expressed cluster. These novG strains produced only 2 % of the novobiocin formed by the S. coelicolor M512 strains carrying the intact novobiocin cluster. The production could be restored by introducing an intact copy of novG into the mutant. The presence of novG on a multicopy plasmid in the strain containing the intact cluster led to almost threefold overproduction of the antibiotic, suggesting that novobiocin biosynthesis is limited by the availability of NovG protein. Furthermore, purified N-terminal His₆-tagged NovG showed specific DNA-binding activity for the novG–novH and the cloG–cloY intergenic regions of the novobiocin and clorobiocin biosynthetic gene clusters, respectively. By comparing the DNA sequences of the fragments binding NovG, conserved inverted repeats were identified in both fragments, similar to those identified as the binding sites for StrR. The consensus sequence for the StrR and the putative NovG binding sites was GTTCRACTG(N)₁₁CRGTYGAAC. Therefore, NovG and StrR apparently belong to the same family of DNA-binding regulatory proteins.

The GenBank/EMBL/DDBJ accession numbers for the genes and DNA regions used in this study are AF170880 (novobiocin cluster) and AF329398 (clorobiocin cluster).

This article has been cited by other articles:

				R. Alduina, L. L. Piccolo, D. D'Alia, C. Ferraro, N. Gunnarsson, S. Donadio, and A. M. Puglia Phosphate-Controlled Regulator for the Biosynthesis of the Dalbavancin Precursor A40926 J. Bacteriol., November 15, 2007; 189(22): 8120 - 8129. [Abstract] [Full Text] [PDF]

				M. Wolpert, B. Gust, B. Kammerer, and L. Heide Effects of deletions of mbtH-like genes on clorobiocin biosynthesis in Streptomyces coelicolor Microbiology, May 1, 2007; 153(5): 1413 - 1423. [Abstract] [Full Text] [PDF]

				A. Freitag, S.-M. Li, and L. Heide Biosynthesis of the unusual 5,5-gem-dimethyl-deoxysugar noviose: investigation of the C-methyltransferase gene cloU. Microbiology, August 1, 2006; 152(Pt 8): 2433 - 2442. [Abstract] [Full Text] [PDF]