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 Warner, J. B. Articles by Lolkema, J. S. Search for Related Content PubMed PubMed Citation Articles by Warner, J. B. Articles by Lolkema, J. S. Agricola Articles by Warner, J. B. Articles by Lolkema, J. S.

Growth of Bacillus subtilis on citrate and isocitrate is supported by the Mg²⁺–citrate transporter CitM

Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands¹

Author for correspondence: Juke S. Lolkema. Tel: +31 50 3632155. Fax: +31 50 3632154. e-mail: j.s.lolkema{at}biol.rug.nl

Bacillus subtilis 168 was assayed for its growth on tricarboxylic acid (TCA) cycle intermediates and related compounds as the sole carbon sources. Growth of the organism was supported by citrate, D-isocitrate, succinate, fumarate and L-malate, whereas no growth was observed in the presence of cis-aconitate,2-oxoglutarate, D-malate, oxaloacetate and tricarballylate. Growth of the organism on the tricarboxylates citrate and D-isocitrate required the presence of functional CitM, an Mg²⁺–citrate transporter, whereas its growth on succinate, fumarate and L-malate appeared to be CitM-independent. Interestingly, the naturally occurring enantiomer D-isocitrate was favoured over L-isocitrate by the organism. Like citrate, D-isocitrate was shown to be an inducer of citM expression in B. subtilis. The addition of 1 mM Mg²⁺ to the growth medium improved growth of the organism on both citrate and D-isocitrate, suggesting that D-isocitrate was taken up by CitM in complex with divalent metal ions. Subsequently, the ability of CitM to transport D-isocitrate was demonstrated by competition experiments and by heterologous exchange in right-side-out membrane vesicles prepared from E. coli cells expressing citM. None of the other TCA cycle intermediates and related compounds tested were recognized by CitM. Uptake experiments using radioactive ⁶³Ni²⁺ provided direct evidence that D-isocitrate is transported in complex with divalent metal ions.

Keywords: TCA cycle intermediate, promoter fusion, divalent metal ion–citrate complex, membrane vesicles, exchange

Abbreviations: FCCP, carbonylcyanide p-trifluormethoxy-phenylhydrazone; MSMYE, minimal salts medium/0·05% yeast extract; RSO, right-side-out; TCA, tricarboxylic acid

This article has been cited by other articles:

				F. D. Ernst, J. Stoof, W. M. Horrevoets, E. J. Kuipers, J. G. Kusters, and A. H. M. van Vliet NikR Mediates Nickel-Responsive Transcriptional Repression of the Helicobacter pylori Outer Membrane Proteins FecA3 (HP1400) and FrpB4 (HP1512) Infect. Immun., December 1, 2006; 74(12): 6821 - 6828. [Abstract] [Full Text] [PDF]

				Y. Wei, G. Deikus, B. Powers, V. Shelden, T. A. Krulwich, and D. H. Bechhofer Adaptive Gene Expression in Bacillus subtilis Strains Deleted for tetL. J. Bacteriol., October 1, 2006; 188(20): 7090 - 7100. [Abstract] [Full Text] [PDF]

				B. Gorke, E. Foulquier, and A. Galinier YvcK of Bacillus subtilis is required for a normal cell shape and for growth on Krebs cycle intermediates and substrates of the pentose phosphate pathway Microbiology, November 1, 2005; 151(11): 3777 - 3791. [Abstract] [Full Text] [PDF]

				D. Gunzel, K. Hintz, S. Durry, and W.-R. Schlue Mg2+-Malate Co-Transport, a Mechanism for Na+-Independent Mg2+ Transport in Neurons of the Leech Hirudo medicinalis J Neurophysiol, July 1, 2005; 94(1): 441 - 453. [Abstract] [Full Text] [PDF]

				J. B. Warner, C. Magni, and J. S. Lolkema CcpA-Independent Regulation of Expression of the Mg2+-Citrate Transporter Gene citM by Arginine Metabolism in Bacillus subtilis J. Bacteriol., February 1, 2003; 185(3): 854 - 859. [Abstract] [Full Text] [PDF]