1GG8

DESIGN OF INHIBITORS OF GLYCOGEN PHOSPHORYLASE: A STUDY OF ALPHA-AND BETA-C-GLUCOSIDES AND 1-THIO-BETA-D-GLUCOSE COMPOUNDS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.202 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Design of inhibitors of glycogen phosphorylase: a study of alpha- and beta-C-glucosides and 1-thio-beta-D-glucose compounds.

Watson, K.A.Mitchell, E.P.Johnson, L.N.Son, J.C.Bichard, C.J.Orchard, M.G.Fleet, G.W.Oikonomakos, N.G.Leonidas, D.D.Kontou, M.Papageorgioui, A.

(1994) Biochemistry 33: 5745-5758


  • PubMed Abstract: 
  • alpha-D-Glucose is a weak inhibitor of glycogen phosphorylase b (Ki = 1.7 mM) and acts as a physiological regulator of hepatic glycogen metabolism. Glucose binds to phosphorylase at the catalytic site and results in a conformational change that stabi ...

    alpha-D-Glucose is a weak inhibitor of glycogen phosphorylase b (Ki = 1.7 mM) and acts as a physiological regulator of hepatic glycogen metabolism. Glucose binds to phosphorylase at the catalytic site and results in a conformational change that stabilizes the inactive T state of the enzyme, promoting the action of protein phosphatase 1 and stimulating glycogen synthase. It has been suggested that, in the liver, glucose analogues with greater affinity for glycogen phosphorylase may result in a more effective regulatory agent. Several alpha- and beta-anhydroglucoheptonic acid derivatives and 1-deoxy-1-thio-beta-D-glucose analogues have been synthesized and tested in a series of crystallographic and kinetic binding studies with glycogen phosphorylase. The structural results of the bound enzyme-ligand complexes have been analyzed, together with the resulting affinities, in an effort to understand and exploit the molecular interactions that might give rise to a better inhibitor. This work has shown the following: (i) Similar affinities may be obtained through different sets of interactions. Specifically, in the case of the alpha- and beta-glucose-C-amides, similar Ki's (0.37 and 0.44 mM, respectively) are obtained with the alpha-anomer through interactions from the ligand via water molecules to the protein and with the beta-anomer through direct interaction from the ligand to the protein. Thus, hydrogen bonds through water can contribute binding energy similar to that of hydrogen bonds directly to the protein. (ii) Attempts to improve the inhibition by additional groups did not always lead to the expected result. The addition of nonpolar groups to the alpha-carboxamide resulted in a change in conformation of the pyranose ring from a chair to a skew boat and the consequent loss of favorable hydrogen bonds and increase in the Ki. (iii) The addition of polar groups to the alpha-carboxamide led to compounds with the chair conformation, and in the examples studied, it appears that hydration by a water molecule may provide sufficient stabilization to retain the chair conformation. (iv) The best inhibitor was N-methyl-beta-glucose-C-carboxamide (Ki = 0.16 mM), which showed a 46-fold improvement in Ki from the parent beta-D-glucose. The decrease in Ki may be accounted for by a single hydrogen bond from the amide nitrogen to a main-chain carbonyl oxygen, an increase in entropy through displacement of a water molecule, and favorable van der Waals contacts between the methyl substituent and nonpolar protein residues.(ABSTRACT TRUNCATED AT 250 WORDS)


    Related Citations: 
    • N-Acetyl-Beta-D-Glucopyranosylamine: A Potent T-State Inhibitor of Glycogen Phosphorylase. A Comparison with Alpha-D-Glucose
      Oikonomakos, N.G.,Kontou, M.,Zographos, S.E.,Watson, K.A.,Johnson, L.N.,Bichard, C.J.,Fleet, G.W.,Acharya, K.R.
      (1995) Protein Sci. 4: 2469


    Organizational Affiliation

    Oxford Centre for Molecular Sciences, U.K.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PROTEIN (GLYCOGEN PHOSPHORYLASE)
A
842Oryctolagus cuniculusGene Names: PYGM
EC: 2.4.1.1
Find proteins for P00489 (Oryctolagus cuniculus)
Go to Gene View: PYGM
Go to UniProtKB:  P00489
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
IMP
Query on IMP

Download SDF File 
Download CCD File 
A
INOSINIC ACID
C10 H13 N4 O8 P
GRSZFWQUAKGDAV-KQYNXXCUSA-N
 Ligand Interaction
GLG
Query on GLG

Download SDF File 
Download CCD File 
A
ALPHA-D-GLUCOPYRANOSYL-2-CARBOXYLIC ACID AMIDE
C7 H13 N O6
UKWLGCFJAVEFPE-DVKNGEFBSA-N
 Ligand Interaction
PLP
Query on PLP

Download SDF File 
Download CCD File 
A
PYRIDOXAL-5'-PHOSPHATE
VITAMIN B6 Phosphate
C8 H10 N O6 P
NGVDGCNFYWLIFO-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
GLGKi: 370000 - 436516 nM (99) BINDINGDB
GLGKi: 1000000 nM BINDINGMOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.202 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 128.500α = 90.00
b = 128.500β = 90.00
c = 116.300γ = 90.00
Software Package:
Software NamePurpose
CCP4model building
XDSdata reduction
X-PLORrefinement
CCP4phasing
XDSdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-08-23
    Type: Initial release
  • Version 1.1: 2008-04-26
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance
  • Version 1.3: 2012-02-22
    Type: Database references