Get   for     ? 
 Site search     ? 
Catalytic Site Atlas Version 2.2.12
Find Annotated Site: PDB code:
Swiss-Prot code:
EC number:
Help
CSA entry for 2f9z
Original Entry
Title:
Signaling protein
Compound:
Chemotaxis protein chec
Mutant:
No
UniProt/Swiss-Prot:
-
Q9X005-Q9X005_THEMA
Q9X006-Q9X006_THEMA
EC Class:
3.1.1.61
3.5.1.44
Other CSA Entries:
Overview of all sites for 2f9z
Homologues of 2f9z
Entries for UniProt/Swiss-Prot: 
Entries for UniProt/Swiss-Prot: Q9X005
Entries for UniProt/Swiss-Prot: Q9X006
Entries for EC: 3.1.1.61
Entries for EC: 3.5.1.44
Other Databases:
PDB entry: 2f9z
PDBsum entry: 2f9z
UniProt/Swiss-Prot: 
UniProt/Swiss-Prot: Q9X005
UniProt/Swiss-Prot: Q9X006
IntEnz entry: 3.1.1.61
IntEnz entry: 3.5.1.44
Literature Report:
Introduction:
CheD is a regulatory protein involved in the signal transduction pathways that contorol bacterial chemotaxis. CheD deamidates receptor glutamine residues contained within a conserved structural motif and also hydrolyses glutamyl-methyl-esters at specific positions on it's target proteins. This pdb (2f9z) contains the structure of the CheC:CheD complex from Thermotoga maritima. CheC is a signal-terminating phosphatase which down regulates CheD activity by mimicking the substrate.
Mechanism:
A mechanism analogous to that seen in cysteine proteases, such as papain, has been proposed for the deamidation. Cys27 acts as the nucleophile. It attacks the carbonyl carbon of the substrate yielding a tetrahedral intermediate. Ammonia is lost yielding a thioester which is hydrolysed by a water molecule.

Sites:

Click to Display Catalytic Site (Get help with this section)
Found by:
Literature reference 

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
THRC 21 21Sidechain
ElectrostaticResidue
Stabilises the positions of His44 and Cys27.
Evidence from paper Evidence concerns Evidence type
PubMed ID 16469702 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 16469702 Current protein Conservation of residue
PubMed ID 16469702 Current protein Mutagenesis of residue

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
CYSC 27 27Sidechain
NucleophileSubstrate
Cys27 is the nucleophile which attacks the carbonyl carbon of the substrate.
Evidence from paper Evidence concerns Evidence type
PubMed ID 16469702 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 16469702 Current protein Conservation of residue
PubMed ID 16469702 Current protein Mutagenesis of residue
PubMed ID 16469702 Current protein Structural similarity to homologue of known mechanism
PubMed ID 16469702 Current protein Ligand is essential for catalysis

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
HISC 44 44Sidechain
Acid/baseTransition state
Acid/baseResidue
His44 deprotonates Cys27 so that it may act as nucleophile. His44 may also protonate the amino-leaving group of the substrate.
Evidence from paper Evidence concerns Evidence type
PubMed ID 16469702 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 16469702 Current protein Ligand is essential for catalysis
PubMed ID 16469702 Current protein Conservation of residue
PubMed ID 16469702 Current protein Mutagenesis of residue
PubMed ID 16469702 Current protein Structural similarity to homologue of known mechanism
Notes:

References:
Which EBI biological databases are available and how do I access them? EBI Site Map