PDBsum entry 2qcs

Transferase/transferase inhibitor

PDB id: 2qcs

Contents

Protein chains

338 a.a. *

291 a.a. *

Ligands

SO4 ×6

ACT

ANP

TAM

GOL ×3

Metals

_MN ×2

Waters ×289

* Residue conservation analysis

PDB id:

2qcs

Name:

Transferase/transferase inhibitor

Title:

A complex structure between the catalytic and regulatory subunit of protein kinase a that represents the inhibited state

Structure:

Camp-dependent protein kinase, alpha-catalytic subunit. Chain: a. Fragment: catalytic subunit. Synonym: pka c-alpha. Engineered: yes. Camp-dependent protein kinase type i-alpha regulatory subunit. Chain: b. Fragment: regulatory subunit.

Source:

Mus musculus. House mouse. Organism_taxid: 10090. Gene: prkaca, pkaca. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Bos taurus. Cattle. Organism_taxid: 9913.

Resolution:

2.20Å R-factor: 0.194 R-free: 0.225

Authors:

C.Kim,C.Y.Cheng,A.S.Saldanha,S.S.Taylor

Key ref:

C.Kim et al. (2007). PKA-I Holoenzyme Structure Reveals a Mechanism for cAMP-Dependent Activation. Cell, 130, 1032-1043. PubMed id: 17889648 DOI: 10.1016/j.cell.2007.07.018

Date:

19-Jun-07 Release date: 06-Nov-07

Protein chain

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

Seq: 351 a.a.

Struc: 338 a.a.*

Protein chain

P00514  (KAP0_BOVIN) -  cAMP-dependent protein kinase type I-alpha regulatory subunit from Bos taurus

Seq: 380 a.a.

Struc: 291 a.a.*

* PDB and UniProt seqs differ at 2 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] + ATP = O-phospho-L-seryl-[protein] (Bound ligand (Het Group name = ANP) matches with 81.25% similarity) + ADP + H(+)

L-threonyl-[protein] + ATP = O-phospho-L-threonyl-[protein] (Bound ligand (Het Group name = ANP) matches with 81.25% similarity) + ADP + H(+)

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

reference

DOI no: 10.1016/j.cell.2007.07.018

Cell 130:1032-1043 (2007)

PubMed id: 17889648

PKA-I Holoenzyme Structure Reveals a Mechanism for cAMP-Dependent Activation.

C.Kim, C.Y.Cheng, S.A.Saldanha, S.S.Taylor.

ABSTRACT

Protein kinase A (PKA) holoenzyme is one of the major receptors for cyclic adenosine monophosphate (cAMP), where an extracellular stimulus is translated into a signaling response. We report here the structure of a complex between the PKA catalytic subunit and a mutant RI regulatory subunit, RIalpha(91-379:R333K), containing both cAMP-binding domains. Upon binding to the catalytic subunit, RI undergoes a dramatic conformational change in which the two cAMP-binding domains uncouple and wrap around the large lobe of the catalytic subunit. This large conformational reorganization reveals the concerted mechanism required to bind and inhibit the catalytic subunit. The structure also reveals a holoenzyme-specific salt bridge between two conserved residues, Glu261 and Arg366, that tethers the two adenine capping residues far from their cAMP-binding sites. Mutagenesis of these residues demonstrates their importance for PKA activation. Our structural insights, combined with the mutagenesis results, provide a molecular mechanism for the ordered and cooperative activation of PKA by cAMP.

Selected figure(s)

Figure 1.
Figure 1. Overview of the PKA RIα(91–379):C Holoenzyme Complex
Top: domain organization of the catalytic and regulatory subunits. The two red spheres indicate the phosphorylation sites Thr197^C and Ser338^C in the catalytic subunit.
(A and C) (A) shows a view of the inhibitor sequence of the regulatory subunit bound to the active-site cleft of the catalytic subunit. Boxed regions indicate interaction sites between the R and C subunits at the active site (site 1, left) and the αG helix (site 2, right). (C) shows a 180° rotation of the view in (A). Boxed regions indicate the interaction site at the activation loop (site 3, top) and αH-αI loop (site 4, bottom). The regulatory subunit is shown as a cartoon representation with domain A in dark teal, domain B in cyan, the phosphate-binding cassette (PBC) in yellow, and the αB/C helix and inhibitor site in dark red.
(B and D) Surface representation of both subunits in the same view as in (A) and (C), respectively. The catalytic subunit is bound to AMP-PNP (black sticks) and Mn^2+ (blue spheres) with the small lobe (light tan) and the large lobe (dark tan) in surface rendering.

Figure 6.
Figure 6. Binding of the Catalytic Subunit Reorganizes the N3A Motif and the Phosphate-Binding Cassette in the Regulatory Subunit to Create a Contiguous Hydrophobic Interface
(A) Comparison of the helical regions in domain A between the cAMP (left) and catalytic subunit-bound (right) conformations. Movement of the helical regions is mediated by hydrophobic rearrangement of the hinge residues in the PBC (Ile203^R and Leu204^R), αB helix (Tyr229^R), and 3[10] loop (Leu135^R).
(B) Comparison of domain B in the cAMP and catalytic subunit-bound conformations, highlighting the C-terminal tail (red). In domain B, the helical rearrangements are similar to domain A where residues in the PBC (Leu327^R and Leu328^R), αB helix (Phe353^R), and 3[10] loop (Ile253^R and Leu254^R) come together.
(C) Comparison between domains A and B in the holoenzyme conformation. In domain A, the N3A motif (residues 123–150) and PBC come together and serve as a docking surface for the P+1 loop (black) and the αG helix (dark tan) of the catalytic subunit. In domain B, a similar hydrophobic interface is formed between the N3A motif (residues 245–367) and PBC; however, the C-terminal tail (αB, αC′, and αC″ helices) lies on top of the hydrophobic interface.

The above figures are reprinted by permission from Cell Press: Cell (2007, 130, 1032-1043) copyright 2007.

Figures were selected by an automated process.