CysK

• Description: trigger enzyme: cysteine synthetase A and control of CymR activity
  
  

Gene name	cysK
Synonyms
Essential	no
Product	trigger enzyme: cysteine synthetase A
Function	biosynthesis of cysteine, control of CymR activity
Metabolic function and regulation of this protein in SubtiPathways: Cys, Met & Sulfate assimilation
MW, pI	32 kDa, 5.492
Gene length, protein length	924 bp, 308 aa
Immediate neighbours	yacD, pabB
Get the DNA and protein sequences (Barbe et al., 2009)
Genetic context This image was kindly provided by SubtiList

Categories containing this gene/protein

biosynthesis/ acquisition of amino acids, transcription factors and their control, trigger enzyme

This gene is a member of the following regulons

CymR regulon, Spx regulon

The gene

Basic information

• Locus tag: BSU00730

Phenotypes of a mutant

constitutive expression of the cysH-cysP-sat-cysC-ylnD-ylnE-ylnF operon, auxotrophic for cysteine

Database entries

• DBTBS entry: [1]

• SubtiList entry: [2]

The protein

Basic information/ Evolution

• Catalyzed reaction/ biological activity: O(3)-acetyl-L-serine + H₂S = L-cysteine + acetate (according to Swiss-Prot)

• Protein family: cysteine synthase/cystathionine beta-synthase family (according to Swiss-Prot)

• Paralogous protein(s):

Extended information on the protein

• Kinetic information:

• Domains:

• Modification:

• Cofactor(s):

• Effectors of protein activity:

• Interactions:
  • CymR-CysK, the complex is formed in the presence of cysteine, and results in DNA binding and repression of genes of cysteine biosynthesis PubMed

• Localization:

Database entries

• Structure: 1Y7L (from Haemophilus influenzae, 39% identity, 52% similarity) PubMed

• UniProt: P37887

• KEGG entry: [3]

• E.C. number: 2.5.1.47

Expression and regulation

• Operon: cysK PubMed

• Sigma factor: SigA PubMed

• Regulation:
  • repressed by casamino acids PubMed
  • repressed in the presence of cysteine (CymR) PubMed

• Regulatory mechanism:
  • CymR: transcription repression PubMed
  • Spx: transcription activation PubMed

• Additional information:

Biological materials

• Mutant:

• Expression vector:

• lacZ fusion:

• GFP fusion:

• two-hybrid system:

• Antibody:

Labs working on this gene/protein

Isabelle Martin-Verstraete, Institute Pasteur, Paris, France