Non-specific serine/threonine protein kinase

 

The control of sporulation in some bacteria is controlled by sigma factors, one of which is sigma-F which triggers the cascade of gene expression in the forespore compartment of the sporulating cell. Control of sigma-F is by the SpoII proteins: SpoIIAB, which binds to sigma-F and thereby inactivates it; SpoIIAA, a non-enzymatic protein which is phosphorylated by SpoIIAB, thus inducing release of sigma-F; and SpoIIE, a phosphatase which returns SpoII-P to the dephosphorylated state. SpoIIAB has the same ATP-binding domain as other members of the GHKL superfamily. It phosphorylates the Ser 58 residue of SpoIIAA, using up ATP.

 

Reference Protein and Structure

Sequences
O32727 UniProt (2.7.11.1)
O32728 UniProt IPR010194 (Sequence Homologues) (PDB Homologues)
Biological species
Geobacillus stearothermophilus (Bacteria) Uniprot
PDB
1l0o - Crystal Structure of the Bacillus stearothermophilus Anti-Sigma Factor SpoIIAB with the Sporulation Sigma Factor SigmaF (2.9 Å) PDBe PDBsum 1l0o
Catalytic CATH Domains
3.30.565.10 CATHdb (see all for 1l0o)
Cofactors
Magnesium(2+) (1)
Click To Show Structure

Enzyme Reaction (EC:2.7.11.1)

L-serine residue
CHEBI:29999ChEBI
+
ATP(4-)
CHEBI:30616ChEBI
→
ADP(3-)
CHEBI:456216ChEBI
+
hydron
CHEBI:15378ChEBI
+
O-phospho-L-serine(2-) residue
CHEBI:83421ChEBI
Alternative enzyme names: Beta-adrenergic receptor kinase, Beta-IIPKC, Epsilon PKC, A-kinase, AP50 kinase, ATP-protein transphosphorylase, CK-2, CKI, CKII, Hpr kinase, M phase-specific cdc2 kinase, MAPK, PKA, PKC, Raf kinase, Raf-1, T-antigen kinase, cAMP-dependent protein kinase, cAMP-dependent protein kinase A, cGMP-dependent protein kinase, Calcium-dependent protein kinase C, Calcium/phospholipid-dependent protein kinase, Casein kinase, Casein kinase (phosphorylating), Casein kinase 2, Casein kinase I, Casein kinase II, Cyclic AMP-dependent protein kinase, Cyclic AMP-dependent protein kinase A, Cyclic monophosphate-dependent protein kinase, Cyclic nucleotide-dependent protein kinase, Cyclin-dependent kinase, Cytidine 3',5'-cyclic monophosphate-responsive protein kinase, Glycogen synthase a kinase, Glycogen synthase kinase, Hydroxyalkyl-protein kinase, Mitogen-activated S6 kinase, Mitogen-activated protein kinase, P82 kinase, Phosphorylase b kinase kinase, Protein glutamyl kinase, Protein kinase (phosphorylating), Protein kinase A, Protein kinase CK2, Protein kinase p58, Protein phosphokinase, Protein serine kinase, Protein serine-threonine kinase, Protein-aspartyl kinase, Protein-cysteine kinase, Protein-serine kinase, Ribosomal S6 protein kinase, Ribosomal protein S6 kinase II, Serine kinase, Serine protein kinase, Serine(threonine) protein kinase, Serine-specific protein kinase, Serine/threonine protein kinase, Threonine-specific protein kinase, Twitchin kinase, Type-2 casein kinase, Phosphorylase B kinase kinase, Glycogen synthase A kinase, HIPK2, Wee 1-like kinase, WEE1Hu, Prp4 protein kinase, Dsk1, STK32, Wee-kinase,

Enzyme Mechanism

Introduction

The basic mechanism is the inline displacement of ADP, by nucleophilic attack of the SpoIIAA Ser 58 on the gamma-phosphate of ATP. Various residues and an Mg cofactor aid the reaction: Mg2+, bound by Asn 50 coordinates all three phosphate groups of ATP. This stabilises the transition state by reducing charge build-up. Arg 105 is in the correct position to stabilise the transition state by hydrogen bonding to two oxygens of the gamma-phosphate group. Glu 46 is the catalytic base.

Catalytic Residues Roles

UniProt PDB* (1l0o)
Asn50 Asn50A Chelates to the magnesium ion cofactor. metal ligand
Glu46 Glu46A Glu 46 hydrogen bonds to the SpoIIAA Ser 58 hydroxyl, and probably acts as the catalytic base. proton acceptor, activator, electrostatic stabiliser
Arg105 Arg105A Arg 105 stabilises the transition state by hydrogen bonding to two oxygens of the gamma-phosphate group. electrostatic stabiliser, polar interaction
*PDB label guide - RESx(y)B(C) - RES: Residue Name; x: Residue ID in PDB file; y: Residue ID in PDB sequence if different from PDB file; B: PDB Chain; C: Biological Assembly Chain if different from PDB. If label is "Not Found" it means this residue is not found in the reference PDB.

Chemical Components

bimolecular nucleophilic substitution, overall product formed, overall reactant used, inferred reaction step, proton transfer

References

  1. Campbell EA et al. (2002), Cell, 108, 795-807. Crystal structure of the Bacillus stearothermophilus anti-sigma factor SpoIIAB with the sporulation sigma factor sigmaF. DOI:10.2210/pdb1l0o/pdb. PMID:11955433.
  2. Masuda S et al. (2004), J Mol Biol, 340, 941-956. Crystal Structures of the ADP and ATP Bound Forms of the Bacillus Anti-σ Factor SpoIIAB in Complex with the Anti-anti-σ SpoIIAA. DOI:10.1016/j.jmb.2004.05.040. PMID:15236958.

Step 1. Glu46 activates the Ser substrate by accepting a proton from it. Serine then attacks the gamma phosphate group from ATP, which gets displaced.

Download: Image, Marvin File

Catalytic Residues Roles

Residue Roles
Glu46A electrostatic stabiliser
Arg105A electrostatic stabiliser
Glu46A activator
Asn50A metal ligand
Arg105A polar interaction
Glu46A proton acceptor

Chemical Components

ingold: bimolecular nucleophilic substitution, overall product formed, overall reactant used, inferred reaction step, proton transfer
Download: Image, Marvin File

Step 1. Glu46 activates the Ser substrate by accepting a proton from it. Serine then attacks the gamma phosphate group from ATP, which gets displaced.

Products.

Contributors

Jonathan T. W. Ng, Gemma L. Holliday, Morwenna Hall