CitB

• Description: Trigger enzyme: aconitase and RNA binding protein
  
  

Gene name	citB
Synonyms
Essential	no
Product	aconitate hydratase (aconitase)
Function	TCA cycle
Metabolic function and regulation of this protein in SubtiPathways: Central C-metabolism
MW, pI	99 kDa, 4.903
Gene length, protein length	2727 bp, 909 aa
Immediate neighbours	sspO, yneN
Get the DNA and protein sequences (Barbe et al., 2009)
Genetic context This image was kindly provided by SubtiList

The gene

Basic information

• Locus tag: BSU18000

Phenotypes of a mutant

glutamate auxotrophy and a defect in sporulation PubMed

Database entries

• DBTBS entry: [1]

• SubtiList entry: [2]

The protein

Basic information/ Evolution

• Catalyzed reaction/ biological activity: Citrate = isocitrate (according to Swiss-Prot)
  • Binding to iron responsive elements (IRE RNA) in the absence of the FeS cluster PubMed

• Protein family:

• Paralogous protein(s):

Extended information on the protein

• Kinetic information:

• Domains:

• Modification:

• Cofactor(s): FeS cluster

• Effectors of protein activity:

• Interactions:

• Localization:

Database entries

• Structure: 1L5J (E. coli)

• Swiss prot entry: P09339

• KEGG entry: [3]

• E.C. number: 4.2.1.3

Additional information

B. subtilis aconitase is both an enzyme and an RNA binding protein PubMed

Expression and regulation

• Operon: citB

• Sigma factor: SigA

• Regulation:
  • repressed during growth in the presence of branched chain amino acids (CodY) PubMed
  • repressed in the presence of glucose and glutamate (CcpC) PubMed
  • expressed upon transition into the stationary phase (AbrB) PubMed
  • repressed by glucose (3.7-fold) (CcpA) PubMed
  • repression by glucose + arginine (CcpC) PubMed
  • less expressed under conditions of extreme iron limitation (FsrA) PubMed

• Regulatory mechanism:
  • CodY: transcription repression PubMed
  • CcpC: transcription repression (molecular inducer: citrate) PubMed
  • AbrB: transcription activation PubMed
  • CcpA: transcription repression
  • CcpC: transcription repression PubMed
  • AbrB: transcription activation PubMed
  • FsrA: translational repression PubMed

• Additional information:

Biological materials

• Mutant: GP683 (erm), available in Stülke lab

• Expression vector:

• lacZ fusion:

• GFP fusion:

• two-hybrid system: B. pertussis adenylate cyclase-based bacterial two hybrid system (BACTH), available in Stülke lab

• Antibody: available in Linc Sonenshein lab

Labs working on this gene/protein

Linc Sonenshein, Tufts University, Boston, MA, USA Homepage

Jörg Stülke, University of Göttingen, Germany Homepage

References

1. Blencke et al. (2003) Transcriptional profiling of gene expression in response to glucose in Bacillus subtilis: regulation of the central metabolic pathways. Metab Eng. 5: 133-149 PubMed
2. Rosenkrantz MS, Dingman DW, Sonenshein AL (1985) Bacillus subtilis citB gene is regulated synergistically by glucose and glutamine. J Bacteriol 164:155-164. PubMed
3. Jourlin-Castelli C, Mani N, Nakano MM, Sonenshein AL (2000) CcpC, a novel regulator of the LysR family required for glucose repression of the citB gene in Bacillus subtilis. J Mol Biol 295:865-878. PubMed
4. Alén C, Sonenshein AL (1999) Bacillus subtilis aconitase is an RNA-binding protein. Proc Natl Acad Sci USA 96:10412-10417. PubMed
5. Fisher SH, Magasanik B (1984) 2-Ketoglutarate and the regulation of aconitase and histidase formation Bacillus subtilis. J Bacteriol 158:379-382. PubMed
6. Kim, H. J., S. I. Kim, M. Ratnayake-Lecamwasam, K. Tachikawa, A. L. Sonenshein, and M. Strauch. (2003) Complex regulation of the Bacillus subtilis aconitase gene. J. Bacteriol. 185:1672-1680. PubMed
7. Blencke, H.-M., Reif, I., Commichau, F. M., Detsch, C., Wacker, I., Ludwig, H. & Stülke, J. (2006) Regulation of citB expression in Bacillus subtilis: Integration of multiple metabolic signals in the citrate pool and by the general nitrogen regulatory system. Arch. Microbiol. 185: 136-146. PubMed
8. Serio, A. W., Pechter, K. B., and Sonenshein, A. L. (2006) Bacillus subtilis aconitase is required for efficient late-sporulation gene expression. J Bacteriol 188: 6396-6405. PubMed
9. Nakano MM, Zuber P, Sonenshein AL (1998) Anaerobic regulation of Bacillus subtilis Krebs cycle genes. J Bacteriol. 180:3304-3311. PubMed
10. Craig JE, Ford MJ, Blaydon DC, Sonenshein AL (1997) A null mutation in the Bacillus subtilis aconitase gene causes a block in Spo0A-phosphate-dependent gene expression. J Bacteriol 197:7351-7359. PubMed
11. Kim HJ, Kim SI, Ratnayake-Lecamwasam M, Tachikawa K, Sonenshein AL, Strauch M (2003) Complex regulation of the Bacillus subtilis aconitase gene. J Bacteriol. 185:1672-1680. PubMed
12. Fouet, A., and Sonenshein, A. L. (1990) A target for carbon source-dependent negative regulation of the citB promoter of Bacillus subtilis. J Bacteriol 172: 835-844. PubMed
13. Author1, Author2 & Author3 (year) Title Journal volume: page-page. PubMed