RocG

• Description: trigger enzyme: catabolic glutamate dehydrogenase induced by arginine, ornithine or proline, subject to carbon catabolite repression
  
  

Gene name	rocG
Synonyms
Essential	no
Product	trigger enzyme: glutamate dehydrogenase (major)
Function	arginine utilization, controls the activity of GltC
Gene expression levels in SubtiExpress: rocG
Interactions involving this protein in SubtInteract: RocG
Metabolic function and regulation of this protein in SubtiPathways: rocG
MW, pI	46.2 kDa, 6.28
Gene length, protein length	1272 bp, 424 amino acids
Immediate neighbours	rocA, sivA
Sequences	Protein DNA DNA_with_flanks
Genetic context This image was kindly provided by SubtiList
Expression at a glance   PubMed

Categories containing this gene/protein

utilization of amino acids, glutamate metabolism, transcription factors and their control, trigger enzyme

This gene is a member of the following regulons

AbrB regulon, AhrC regulon, CcpA regulon, RocR regulon, SigL regulon

The gene

Basic information

• Locus tag: BSU37790

Phenotypes of a mutant

• Poor growth on complex media such as SP (sporulation medium). No growth in minimal media with arginine as the only carbon source. Rapid accumulation of suppressor mutants (gudB1)
• sensitive to ß-lactam antibiotics such as cefuroxime and to fosfomycin (suppressed by activation of gudB) due to the downregulation of the SigW regulon PubMed
• transcription profile of a rocG gudB mutant strain: GEO PubMed

Database entries

• BsubCyc: BSU37790

• DBTBS entry: [1]

• SubtiList entry: [2]

• GEO entry: [3] (rocG gudB mutant vs. wild type)

The protein

Basic information/ Evolution

• Catalyzed reaction/ biological activity: L-glutamate + H₂O + NAD⁺ = 2-oxoglutarate + NH₃ + NADH + H⁺ (according to Swiss-Prot), controls the activity of the GltC transcription activator PubMed

• Protein family: Glu/Leu/Phe/Val dehydrogenases family (according to Swiss-Prot)

• Paralogous protein(s): GudB

Extended information on the protein

• Kinetic information: K_M [glutamate] = 2.9 mM, K_M [ammonium] = 18 mM PubMed

• Domains:

• Modification:

• Cofactor(s): NAD⁺/NADH + H⁺

• Effectors of protein activity:

• Interactions:
  • RocG-GltC, this interaction prevents transcription activation of the gltA-gltB operon by GltC PubMed

• Localization:

Database entries

• BsubCyc: BSU37790

• Structure: 3K92 (super-repressor mutant that is capable of constitutive inactivation of GltC, E93K mutation) PubMed

• UniProt: P39633

• KEGG entry: [4]

• E.C. number: 1.4.1.2

Expression and regulation

• Operon: rocG PubMed

• Expression browser: rocG PubMed

• Sigma factor: SigL PubMed

• Regulation:
  • induced by arginine (RocR, AhrC), ornithine or proline PubMed
  • subject to carbon catabolite repression (CcpA) PubMed

• Regulatory mechanism:
  • RocR: transcription activation PubMed
  • AhrC: transcription activation PubMed
  • CcpA: transcription repression PubMed
  • AbrB: transcription repression PubMed

• Additional information:

Activation by RocR requires binding of RocR to a downstream element PubMed

Biological materials

• Mutant: GP747 (spc), GP726 (aphA3), GP810 (del tet), GP1157 (cat) all available in Jörg Stülke's lab

• Expression vector:
  • expression of native rocG in B. subtilis: pGP529 (in pBQ200), available in Jörg Stülke's lab PubMed
  • for purification of RocG from E. coli carrying an N-terminal Strep-tag: pGP902 (in pGP172), a series of rocG variants is also available in pGP172, available in Jörg Stülke's lab
  • for expression/ purification from E. coli with N-terminal His-tag and thrombin cleavage site, in pWH844: pGP860, available in Jörg Stülke's lab
  • purification from B. subtilis with an N-terminal Strep-tag, for SPINE, (in pGP380): pGP1709, available in Jörg Stülke's lab

• lacZ fusion:

• GFP fusion:

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

• Antibody: available in Jörg Stülke's lab

Labs working on this gene/protein

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

Jörg Stülke, University of Göttingen, Germany Homepage

Fabian Commichau University of Göttingen, Germany Homepage

References

Function in the control of GltC activity

Katrin Gunka, Joseph A Newman, Fabian M Commichau, Christina Herzberg, Cecilia Rodrigues, Lorraine Hewitt, Richard J Lewis, Jörg Stülke
Functional dissection of a trigger enzyme: mutations of the bacillus subtilis glutamate dehydrogenase RocG that affect differentially its catalytic activity and regulatory properties.
J Mol Biol: 2010, 400(4);815-27
[PubMed:20630473] [WorldCat.org] [DOI] (I p)

Christina Herzberg, Lope Andrés Flórez Weidinger, Bastian Dörrbecker, Sebastian Hübner, Jörg Stülke, Fabian M Commichau
SPINE: a method for the rapid detection and analysis of protein-protein interactions in vivo.
Proteomics: 2007, 7(22);4032-5
[PubMed:17994626] [WorldCat.org] [DOI] (P p)

Fabian M Commichau, Christina Herzberg, Philipp Tripal, Oliver Valerius, Jörg Stülke
A regulatory protein-protein interaction governs glutamate biosynthesis in Bacillus subtilis: the glutamate dehydrogenase RocG moonlights in controlling the transcription factor GltC.
Mol Microbiol: 2007, 65(3);642-54
[PubMed:17608797] [WorldCat.org] [DOI] (P p)

Fabian M Commichau, Ingrid Wacker, Jan Schleider, Hans-Matti Blencke, Irene Reif, Philipp Tripal, Jörg Stülke
Characterization of Bacillus subtilis mutants with carbon source-independent glutamate biosynthesis.
J Mol Microbiol Biotechnol: 2007, 12(1-2);106-13
[PubMed:17183217] [WorldCat.org] [DOI] (P p)

Boris R Belitsky, Abraham L Sonenshein
Modulation of activity of Bacillus subtilis regulatory proteins GltC and TnrA by glutamate dehydrogenase.
J Bacteriol: 2004, 186(11);3399-407
[PubMed:15150225] [WorldCat.org] [DOI] (P p)

Structural analysis of glutamate dehydrogenase

Katrin Gunka, Joseph A Newman, Fabian M Commichau, Christina Herzberg, Cecilia Rodrigues, Lorraine Hewitt, Richard J Lewis, Jörg Stülke
Functional dissection of a trigger enzyme: mutations of the bacillus subtilis glutamate dehydrogenase RocG that affect differentially its catalytic activity and regulatory properties.
J Mol Biol: 2010, 400(4);815-27
[PubMed:20630473] [WorldCat.org] [DOI] (I p)

T J Stillman, P J Baker, K L Britton, D W Rice
Conformational flexibility in glutamate dehydrogenase. Role of water in substrate recognition and catalysis.
J Mol Biol: 1993, 234(4);1131-9
[PubMed:8263917] [WorldCat.org] [DOI] (P p)

Bypass of rocG mutations

Katrin Gunka, Lorena Stannek, Rachel A Care, Fabian M Commichau
Selection-driven accumulation of suppressor mutants in bacillus subtilis: the apparent high mutation frequency of the cryptic gudB gene and the rapid clonal expansion of gudB(+) suppressors are due to growth under selection.
PLoS One: 2013, 8(6);e66120
[PubMed:23785476] [WorldCat.org] [DOI] (I e)

Katrin Gunka, Stefan Tholen, Jan Gerwig, Christina Herzberg, Jörg Stülke, Fabian M Commichau
A high-frequency mutation in Bacillus subtilis: requirements for the decryptification of the gudB glutamate dehydrogenase gene.
J Bacteriol: 2012, 194(5);1036-44
[PubMed:22178973] [WorldCat.org] [DOI] (I p)

Lope A Flórez, Katrin Gunka, Rafael Polanía, Stefan Tholen, Jörg Stülke
SPABBATS: A pathway-discovery method based on Boolean satisfiability that facilitates the characterization of suppressor mutants.
BMC Syst Biol: 2011, 5;5
[PubMed:21219666] [WorldCat.org] [DOI] (I e)