GapA

• Description: Glyceraldehyde 3-phosphate dehydrogenase, NAD-dependent, glycolytic enzyme
  
  

Gene name	gapA
Synonyms
Essential	Yes (PubMed)
Product	glyceraldehyde 3-phosphate dehydrogenase
Function	catabolic enzyme in glycolysis
MW, pI	35.7 kDa, 5.03
Gene length, protein length	1005 bp, 335 amino acids
Immediate neighbours	cggR, pgk
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: BSU33940

Phenotypes of a mutant

essential PubMed

Database entries

• DBTBS entry: [1]

• SubtiList entry:[2]

The protein

Basic information/ Evolution

• Catalyzed reaction/ biological activity: D-glyceraldehyde 3-phosphate + phosphate + NAD⁺ = 3-phospho-D-glyceroyl phosphate + NADH (according to Swiss-Prot) glyceraldehyde-3-phosphate dehydrogenase, (NADH-dependent). Catalyzes the reaction from glyceraldehyde-3-phosphate to 1.3-bi-phosphoglycerate. This reaction is part of the glycolysis.

• Protein family: glyceraldehyde-3-phosphate dehydrogenase family (according to Swiss-Prot)

• Paralogous protein(s): GapB

Extended information on the protein

• Kinetic information: K(M) for NAD: 5.7 mM, K(cat) for NAD: 70/sec (determined for GapA from Geobacillus stearothermophilus) PubMed

• Domains:

• Modification:
  • phosphorylation on (Ser-148 OR Ser-151 OR Thr-153 OR Thr-154) PubMed1, PubMed2
  • reversible thiol modifications after exposure to toxic quinones PubMed

• Cofactor(s):

• Effectors of protein activity:

• Interactions:
  • GapA-PtsH: HPr(Ser-46-P) binds GapA resulting in a slight inhibition of enzymatic activity PubMed
  • GapA-Crh: Crh(Ser-46-P) binds GapA resulting in a slight inhibition of enzymatic activity.PubMed

• Localization: cytoplasm (according to Swiss-Prot), Cytoplasm (Homogeneous) PubMed PubMed, loosely membrane associated PubMed

Database entries

• Structure:
  • 3CMC (from Geobacillus stearothermophilus)
  • 1NQO (from Geobacillus stearothermophilus, mutant with cys 149 replaced by ser, complex with NAD+ und D-Glyceraldehyde-3-Phosphate)

• Swiss prot entry: P09124

• KEGG entry: [3]

• E.C. number: 1.2.1.12

Additional information

GAP dehydrogenases from different sources (incl. Geobacillus stearothermophilus) were shown to cleave RNA (PubMed). Moreover, mutations in gapA from B. subtilis can suppress mutations in genes involved in DNA replication (PubMed).

Expression and regulation

• Operon:
  • cggR-gapA-pgk-tpi-pgm-eno
  • cggR-gapA

The primary mRNAs of the operon are highly unstable. The primary mRNA is subject to processing at the very end of the cggR open reading frame. This results in stable mature gapA and gapA-pgk-tpiA-pgm-eno mRNAs. The processing event requires the Rny protein.

• Sigma factor: SigA

• Regulation: expression activated by glucose (10 fold) PubMed, CggR represses the operon in the absence of glycolytic sugars PubMed

• Regulatory mechanism: repression

• Database entries: DBTBS

• Additional information: GapA is one of the most abundant proteins in the cell. In the presence of glucose, there are about 25,000 GapA molecules per cell (PubMed).

Biological materials

• Mutant: essential

• Expression vector: pGP90 (N-terminal Strep-tag, for SPINE, purification from B. subtilis, in pGP380), pGP704 (N-terminal His-tag, in pWH844) (available in Stülke lab)

• lacZ fusion: pGP506 (in pAC7), pGP512 (in pAC6) (available in Stülke lab)

• GFP fusion:

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

• Antibody: available in Stülke lab

Labs working on this gene/protein

Stephane Aymerich, Microbiology and Molecular Genetics, INRA Paris-Grignon, France

Jörg Stülke, University of Göttingen, Germany homepage