PDBsum entry 4xw5

Transferase

PDB id: 4xw5

Contents

Protein chains

337 a.a.

20 a.a.

Ligands

ATP

Metals

_CA ×2

Waters ×333

PDB id:

4xw5

Name:

Transferase

Title:

X-ray structure of pkac with atp, cp20, calcium ions

Structure:

Camp-dependent protein kinase catalytic subunit alpha. Chain: a. Fragment: unp residues 15-351. Synonym: pka c-alpha. Engineered: yes. Camp-dependent protein kinase inhibitor alpha. Chain: b. Synonym: pki-alpha,camp-dependent protein kinase inhibitor, muscle/brain isoform.

Source:

Mus musculus. Mouse. Organism_taxid: 10090. Gene: prkaca, pkaca. Expressed in: escherichia coli. Expression_system_taxid: 562. Synthetic: yes. Oryctolagus cuniculus. Rabbit.

Resolution:

1.95Å R-factor: 0.189 R-free: 0.252

Authors:

O.Gerlits,J.Tian,A.Das,S.Taylor,P.Langan,T.W.Heller,A.Kovalevsky

Key ref:

O.Gerlits et al. (2015). Phosphoryl Transfer Reaction Snapshots in Crystals: INSIGHTS INTO THE MECHANISM OF PROTEIN KINASE A CATALYTIC SUBUNIT. J Biol Chem, 290, 15538-15548. PubMed id: 25925954 DOI: 10.1074/jbc.M115.643213

Date:

28-Jan-15 Release date: 06-May-15

Protein chain

P05132  (KAPCA_MOUSE) -  cAMP-dependent protein kinase catalytic subunit alpha from Mus musculus

Seq: 351 a.a.

Struc: 337 a.a.*

Protein chain

P61926  (IPKA_RABIT) -  cAMP-dependent protein kinase inhibitor alpha from Oryctolagus cuniculus

Seq: 76 a.a.

Struc: 20 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chain A: E.C.2.7.11.11 - cAMP-dependent protein kinase.
• Reaction:
  1. L-seryl-[protein] + ATP = O-phospho-L-seryl-[protein] + ADP + H⁺
  2. L-threonyl-[protein] + ATP = O-phospho-L-threonyl-[protein] + ADP + H⁺

L-seryl-[protein] (Bound ligand (Het Group name = ATP) corresponds exactly) + ATP = O-phospho-L-seryl-[protein] + ADP + H(+)

L-threonyl-[protein] (Bound ligand (Het Group name = ATP) corresponds exactly) + ATP = O-phospho-L-threonyl-[protein] + ADP + H(+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1074/jbc.M115.643213

J Biol Chem 290:15538-15548 (2015)

PubMed id: 25925954

Phosphoryl Transfer Reaction Snapshots in Crystals: INSIGHTS INTO THE MECHANISM OF PROTEIN KINASE A CATALYTIC SUBUNIT.

O.Gerlits, J.Tian, A.Das, P.Langan, W.T.Heller, A.Kovalevsky.

ABSTRACT

To study the catalytic mechanism of phosphorylation catalyzed by cAMP-dependent protein kinase (PKA) a structure of the enzyme-substrate complex representing the Michaelis complex is of specific interest as it can shed light on the structure of the transition state. However, all previous crystal structures of the Michaelis complex mimics of the PKA catalytic subunit (PKAc) were obtained with either peptide inhibitors or ATP analogs. Here we utilized Ca(2+) ions and sulfur in place of the nucleophilic oxygen in a 20-residue pseudo-substrate peptide (CP20) and ATP to produce a close mimic of the Michaelis complex. In the ternary reactant complex, the thiol group of Cys-21 of the peptide is facing Asp-166 and the sulfur atom is positioned for an in-line phosphoryl transfer. Replacement of Ca(2+) cations with Mg(2+) ions resulted in a complex with trapped products of ATP hydrolysis: phosphate ion and ADP. The present structural results in combination with the previously reported structures of the transition state mimic and phosphorylated product complexes complete the snapshots of the phosphoryl transfer reaction by PKAc, providing us with the most thorough picture of the catalytic mechanism to date.