4DFY

Crystal structure of R194A mutant of cAMP-dependent protein kinase with unphosphorylated activation loop

Summary for 4DFY

• Entry DOI: 10.2210/pdb4dfy/pdb
• Related: 1ATP 1J3H
• Descriptor: cAMP-dependent protein kinase catalytic subunit alpha (2 entities in total)
• Functional Keywords: protein kinase fold, serine/threonine kinase activity, camp-dependent protein kinase regulatory subunit, pki, phosphorylation, transferase
• Biological source: Mus musculus (mouse)
• Cellular location: Cytoplasm: P05132
• Total number of polymer chains: 2
• Total formula weight: 85587.53

Authors

Steichen, J.M.,Kuchinskas, M.,Yang, J.,Taylor, S.S. (deposition date: 2012-01-24, release date: 2012-02-15, Last modification date: 2024-10-30)

Primary citation

Steichen, J.M.,Kuchinskas, M.,Keshwani, M.M.,Yang, J.,Adams, J.A.,Taylor, S.S.
Structural basis for the regulation of protein kinase a by activation loop phosphorylation.
J.Biol.Chem., 287:14672-14680, 2012

PubMed Abstract: The catalytic subunit of cAMP-dependent protein kinase (PKA) is a member of the AGC group of protein kinases. Whereas PKA has served as a structural model for the protein kinase superfamily, all previous structures of the catalytic subunit contain a phosphorylated activation loop. To understand the structural effects of activation loop phosphorylation at Thr-197 we used a PKA mutant that does not autophosphorylate at Thr-197. The enzyme crystallized in the apo-state, and the structure was solved to 3.0 Å. The N-lobe is rotated by 18° relative to the wild-type apoenzyme, which illustrates that the enzyme likely exists in a wide range of conformations in solution due to the uncoupling of the N- and C-lobes. Several regions of the protein including the activation loop are disordered in the structure, and there are alternate main chain conformations for the magnesium positioning loop and catalytic loop causing a complete loss of hydrogen bonding between these two active site structural elements. These alterations are reflected in a 20-fold decrease in the apparent phosphoryl transfer rate as measured by pre-steady-state kinetic methods.

PubMed: 22334660
DOI: 10.1074/jbc.M111.335091

Experimental method

X-RAY DIFFRACTION (2.997 Å)