4XW6

X-ray structure of PKAc with ADP, free phosphate ion, CP20, magnesium ions

Summary for 4XW6

• Entry DOI: 10.2210/pdb4xw6/pdb
• Related: 4XW4 4XW5
• Descriptor: cAMP-dependent protein kinase catalytic subunit alpha, cAMP-dependent protein kinase inhibitor alpha, MAGNESIUM ION, ... (6 entities in total)
• Functional Keywords: protein kinase a, atp hydrolysis, catalytic subunit, atpase, transferase
• Biological source: Mus musculus (Mouse); More
• Cellular location: Cytoplasm . Isoform 2: Cell projection, cilium, flagellum : P05132
• Total number of polymer chains: 2
• Total formula weight: 44352.40

Authors

Gerlits, O.,Tian, J.,Das, A.,Taylor, S.,Langan, P.,Heller, T.W.,Kovalevsky, A. (deposition date: 2015-01-28, release date: 2015-05-06, Last modification date: 2023-09-27)

Primary citation

Gerlits, O.,Tian, J.,Das, A.,Langan, P.,Heller, W.T.,Kovalevsky, A.
Phosphoryl Transfer Reaction Snapshots in Crystals: INSIGHTS INTO THE MECHANISM OF PROTEIN KINASE A CATALYTIC SUBUNIT.
J.Biol.Chem., 290:15538-15548, 2015

PubMed 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.

PubMed: 25925954
DOI: 10.1074/jbc.M115.643213

Experimental method

X-RAY DIFFRACTION (1.9 Å)