Interplay of novobiocin-resistant and -sensitive DNA gyrase activities in self-protection of the novobiocin producer, Streptomyces sphaeroides

Thiara, Amrik S.; Cundliffe, Eric

doi:10.1016/0378-1119(89)90337-5

Cited by 43 publications

(49 citation statements)

References 14 publications

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“…In contrast, previous results suggest that the resistance gene gyrB R , at the right border of the cluster depicted in Fig. 4, is under control of its own promoter and may be regulated by changes in DNA superhelical density (Thiara & Cundliffe, 1989). NovG was not required for expression of gyrB R in S. lividans (Thiara & Cundliffe, 1988) and, correspondingly, we did not observe binding of NovG to the promoter sequence of gyrB R in our gel-shift assays.…”

Section: Discussioncontrasting

confidence: 99%

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

Eustáquio

Heide

2005

Microbiology

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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 DnovG 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 His 6 -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) 11 CRGTYGAAC. Therefore, NovG and StrR apparently belong to the same family of DNA-binding regulatory proteins.

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Section: Discussioncontrasting

confidence: 99%

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

Eustáquio

Heide

2005

Microbiology

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“…Although the majority of the self-protective strategies exploited by antibiotic-producing microbes involve intracellular antibiotic modification, cellular target modification, and antibiotic efflux (20)(21)(22), several antibiotic producers have been known to encode antibiotic-resistant target enzymes that contribute to their survival. The bacterial producers of DNA gyrase inhibitors such as aminocoumarins and albicidins are known to encode DNA gyrase-resistant genes that contribute to their self-protection (23,(24)(25)(26), although the molecular mechanism underlying these resistances is still unknown. The D-cycloserine producer Streptomyces lavendulae has been shown to encode an antibiotic-resistant alanine racemase (ALR) that manifests a slower enzymatic conversion to the final cycloserine pyridoxal derivatives that inhibit the catalytic activity of ALR (27,28).…”

Section: Discussionmentioning

confidence: 99%

Andrimid producers encode an acetyl-CoA carboxyltransferase subunit resistant to the action of the antibiotic

Liu

Fortin

Walsh

2008

Proc. Natl. Acad. Sci. U.S.A.

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Andrimid is a hybrid nonribosomal peptide-polyketide antibiotic that blocks the carboxyl-transfer reaction of bacterial acetyl-CoA carboxylase (ACC) and thereby inhibits fatty acid biosynthesis with submicromolar potency. The andrimid biosynthetic gene cluster from Pantoea agglomerans encodes an admT gene with homology to the acetyl-CoA carboxyltransferase (CT) ␤-subunit gene accD. Escherichia coli cells overexpressing admT showed resistance to andrimid. Co-overproduction of AdmT with E. coli CT ␣-subunit AccA allowed for the in vitro reconstitution of an active heterologous tetrameric CT A 2T2 complex. A subsequent andrimidinhibition assay revealed an IC 50 of 500 nM for this hybrid A2T2 in contrast to that of 12 nM for E. coli CT A 2D2. These results validated that AdmT is an AccD homolog that confers resistance in the andrimid producer. Mutagenesis studies guided by the x-ray crystal structure of the E. coli A 2D2 complex disclosed a single amino acid mutation of AdmT (L203M) responsible for 5-fold andrimid sensitivity (IC 50 ‫؍‬ 100 nM). Complementarily, the E. coli AccD mutant M203L became 5-fold more resistant in the CT assays. This observation allowed for bioinformatic identification of several Vibrio cholerae strains in which accD genes encode the Met7Leu switches, and their occurrences correlate predictively with sensitivities to andrimid in vivo.antibiotic resistance ͉ fatty acid biosynthesis inhibitor

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“…In some cases, they lack or modify the target site for the antibiotic (e.g., novobiocin [52] and erythromycin [54]). The resistance gene inactivates the antibiotic through chemical modification in other cases (e.g., bialaphos [30,51]).…”

Section: Discussionmentioning

confidence: 99%

Sequence and transcriptional analysis of the Streptomyces glaucescens tcmAR tetracenomycin C resistance and repressor gene loci

Guilfoile

Hutchinson

1992

J Bacteriol

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Sequence analysis of the tcmA tetracenomycin C resistance gene from Streptomyces glaucescens GLA.O (ETH 22794) identifies one large open reading frame whose deduced product has sequence similarity to the mmr methylenomycin resistance gene from Streptomyces coelicolor, the Streptomyces rimosus tet347 (otrB) tetracycline resistance gene, and the atr1 aminotriazole resistance gene from Saccharomyces cerevisiae. These genes are thought to encode proteins that act as metabolite export pumps powered by transmembrane electrochemical gradients. A divergently transcribed gene, tcmR, is located in the region upstream of tcmA. The deduced product of tcmR resembles the repressor proteins encoded by tetR regulatory genes from Escherichia coli and the actII-orf1 gene from S. coelicolor. Transcriptional analysis of tcmA and tcmR indicates that these genes have back-to-back and overlapping promoter regions.

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Interplay of novobiocin-resistant and -sensitive DNA gyrase activities in self-protection of the novobiocin producer, Streptomyces sphaeroides

Cited by 43 publications

References 14 publications

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

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

Andrimid producers encode an acetyl-CoA carboxyltransferase subunit resistant to the action of the antibiotic

Sequence and transcriptional analysis of the Streptomyces glaucescens tcmAR tetracenomycin C resistance and repressor gene loci

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