Bacillus subtilis IolQ DegA is a transcriptional repressor of iolX encoding NAD -dependent scyllo-inositol dehydrogenaseReport as inadecuate




Bacillus subtilis IolQ DegA is a transcriptional repressor of iolX encoding NAD -dependent scyllo-inositol dehydrogenase - Download this document for free, or read online. Document in PDF available to download.

BMC Microbiology

, 17:154

Microbial biochemistry, physiology and metabolism

Abstract

BackgroundBacillus subtilis is able to utilize at least three inositol stereoisomers as carbon sources, myo-, scyllo-, and D-chiro-inositol MI, SI, and DCI, respectively. NAD-dependent SI dehydrogenase responsible for SI catabolism is encoded by iolX. Even in the absence of functional iolX, the presence of SI or MI in the growth medium was found to induce the transcription of iolX through an unknown mechanism.

ResultsImmediately upstream of iolX, there is an operon that encodes two genes, yisR and iolQ formerly known as degA, each of which could encode a transcriptional regulator. Here we performed an inactivation analysis of yisR and iolQ and found that iolQ encodes a repressor of the iolX transcription. The coding sequence of iolQ was expressed in Escherichia coli and the gene product was purified as a His-tagged fusion protein, which bound to two sites within the iolX promoter region in vitro.

ConclusionsIolQ is a transcriptional repressor of iolX. Genetic evidences allowed us to speculate that SI and MI might possibly be the intracellular inducers, however they failed to antagonize DNA binding of IolQ in in vitro experiments.

KeywordsBacillus subtilis scyllo-inositol Inositol dehydrogenase Transcription Repressor AbbreviationsDCID-chiro-inositol

IPTGisopropyl β-D-1-thiogalactopyranoside

LBlysogeny broth

MImyo-inositol

o-NPo-nitrophenol

PCRpolymerase chain reaction

Pspacspac promoter

SIscyllo-inositol

SISscyllo-inosose

X-gal5-bromo-4-chloro-3-indolyl-β-D-galactoside.

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Author: Dong-Min Kang - Christophe Michon - Tetsuro Morinaga - Kosei Tanaka - Shinji Takenaka - Shu Ishikawa - Ken-ichi Yoshida

Source: https://link.springer.com/







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