1QL6

THE CATALYTIC MECHANISM OF PHOSPHORYLASE KINASE PROBED BY MUTATIONAL STUDIES


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.330 
  • R-Value Work: 0.240 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Catalytic Mechanism of Phosphorylase Kinase Probed by Mutational Studies.

Skamnaki, V.T.Owen, D.J.Noble, M.E.Lowe, E.D.Lowe, G.Oikonomakos, N.G.Johnson, L.N.

(1999) Biochemistry 38: 14718


  • PubMed Abstract: 
  • The contributions to catalysis of the conserved catalytic aspartate (Asp149) in the phosphorylase kinase catalytic subunit (PhK; residues 1-298) have been studied by kinetic and crystallographic methods. Kinetic studies in solvents of different visco ...

    The contributions to catalysis of the conserved catalytic aspartate (Asp149) in the phosphorylase kinase catalytic subunit (PhK; residues 1-298) have been studied by kinetic and crystallographic methods. Kinetic studies in solvents of different viscosity show that PhK, like cyclic AMP dependent protein kinase, exhibits a mechanism in which the chemical step of phosphoryl transfer is fast and the rate-limiting step is release of the products, ADP and phosphoprotein, and possibly viscosity-dependent conformational changes. Site-directed mutagenesis of Asp149 to Ala and Asn resulted in enzymes with a small increase in K(m) for glycogen phosphorylase b (GPb) and ATP substrates and dramatic decreases in k(cat) (1.3 x 10(4) for Asp149Ala and 4.7 x 10(3) for Asp149Asn mutants, respectively). Viscosometric kinetic measurements with the Asp149Asn mutant showed a reduction in the rate-limiting step for release of products by 4.5 x 10(3) and a significant decrease (possibly as great as 2.2 x 10(3)) in the rate constant characterizing the chemical step. The date combined with the crystallographic evidence for the ternary PhK-AMPPNP-peptide complex [Lowe et al. (1997) EMBO J. 6, 6646-6658] provide powerful support for the role of the carboxyl of Asp149 in binding and orientation of the substrate and in catalysis of phosphoryl transfer. The constitutively active subunit PhK has a glutamate (Glu182) residue in the activation segment, in place of a phosphorylatable serine, threonine, or tyrosine residue in other protein kinases that are activated by phosphorylation. Site-directed mutagenesis of Glu182 and other residues involved in a hydrogen bond network resulted in mutant proteins (Glu182Ser, Arg148Ala, and Tyr206Phe) with decreased catalytic efficiency (approximate average decrease in k(cat)/K(m) by 20-fold). The crystal structure of the mutant Glu182Ser at 2.6 A resolution showed a phosphate dianion about 2.6 A from the position previously occupied by the carboxylate of Glu182. There was no change in tertiary structure from the native protein, but the activation segment in the region C-terminal to residue 182 showed increased disorder, indicating that correct localization of the activation segment is necessary in order to recognize and present the protein substrate for catalysis.


    Related Citations: 
    • The Crystal Structure of a Phosphorylase Kinase Peptide Substrate Complex: Kinase Substrate Recognition
      Lowe, E.D.,Noble, M.E.M.,Skamnaki, V.T.,Oikonomakos, N.G.,Owen, D.J.,Johnson, L.N.
      (1997) Embo J. 16: 6646


    Organizational Affiliation

    Institute for Biological Research and Biotechnology, Athens, Greece.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PHOSPHORYLASE KINASE
A
298Oryctolagus cuniculusMutation(s): 1 
Gene Names: PHKG1 (PHKG)
EC: 2.7.11.19
Find proteins for P00518 (Oryctolagus cuniculus)
Go to Gene View: PHKG1
Go to UniProtKB:  P00518
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ATP
Query on ATP

Download SDF File 
Download CCD File 
A
ADENOSINE-5'-TRIPHOSPHATE
C10 H16 N5 O13 P3
ZKHQWZAMYRWXGA-KQYNXXCUSA-N
 Ligand Interaction
MN
Query on MN

Download SDF File 
Download CCD File 
A
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.330 
  • R-Value Work: 0.240 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 47.560α = 90.00
b = 68.171β = 90.00
c = 112.475γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
REFMACrefinement
AMoREphasing
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-12-14
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-07-12
    Type: Derived calculations