Regulation of the transport system for C-4-dicarboxylic acids in Bacillus subtilis

Citation
K. Asai et al., Regulation of the transport system for C-4-dicarboxylic acids in Bacillus subtilis, MICROBIO-UK, 146, 2000, pp. 263-271
Citations number
44
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
MICROBIOLOGY-UK
ISSN journal
1350-0872 → ACNP
Volume
146
Year of publication
2000
Part
2
Pages
263 - 271
Database
ISI
SICI code
1350-0872(200002)146:<263:ROTTSF>2.0.ZU;2-6
Abstract
Transport systems for C-4-dicarboxylates, such as malate, fumarate and succ inate, are poorly understood in Cram-positive bacteria, The whole genome se quence of Bacillus subtilis revealed two genes, ydbE and ydbH, whose deduce d products are highly homologous to binding proteins and transporters for C -4-dicarboxylates in Gram-negative bacteria. Between ydbE and ydbH, genes y dbF and ydbG encoding a sensor-regulator pair, were located. Inactivation o f each one of the ydbEFGH genes caused a deficiency in utilization of fumar ate or succinate but not of malate. Expression of ydbH, encoding a putative transporter, was stimulated in a minimal salt medium containing 0.05% yeas t extract but repressed by the addition of malate to the medium. inactivati on of the putative sensor-regulator pair or solute-binding protein, ydbFG o r ydbE, caused complete loss of ydbH expression. The utilization of fumarat e and stimulation of ydbH expression resumed in a ydbE null mutant in which ydbFGH were overproduced. Based on these observations, together with analy sis of the sequence similarities of the deduced product, we conclude that Y dbH is a C-4-dicarboxylate-transport protein and its expression is regulate d by a C-4-dicarboxylate sensor kinase-regulator pair, YdbF and YdbG. Furth ermore, it is suggested that YdbE does not directly participate in transpor t of C-4-dicarboxylates, but plays a sensory role in the ydbF-ydbG two-comp onent system, giving rise to specificity or increased efficiency to the sys tem. Deletion analysis of the promoter region of ydbH revealed that a direc t repeat sequence was required for the activation of ydbH expression. A cat abolite-responsive element (CRE) was also found in the -10 region of the pr omoter, suggesting negative regulation by a CRE-binding protein.