1NOI

COMPLEX OF GLYCOGEN PHOSPHORYLASE WITH A TRANSITION STATE ANALOGUE NOJIRIMYCIN TETRAZOLE AND PHOSPHATE IN THE T AND R STATES


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.171 
  • R-Value Observed: 0.171 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Ternary complex crystal structures of glycogen phosphorylase with the transition state analogue nojirimycin tetrazole and phosphate in the T and R states.

Mitchell, E.P.Withers, S.G.Ermert, P.Vasella, A.T.Garman, E.F.Oikonomakos, N.G.Johnson, L.N.

(1996) Biochemistry 35: 7341-7355

  • DOI: 10.1021/bi960072w
  • Primary Citation of Related Structures:  
    1NOI, 1NOJ, 1NOK

  • PubMed Abstract: 
  • Catalysis by glycogen phosphorylase involves a mechanism in which binding of one substrate tightens the binding of the other substrate to produce a productive ternary enzyme-substrate complex. In this work the molecular basis for this synergism is probed in crystallographic studies on ternary complexes in which the glucosyl component is substituted by the putative transition state analogue nojirimycin tetrazole, a compound which has been established previously as a transition state analogue inhibitor for a number of glycosidases ...

    Catalysis by glycogen phosphorylase involves a mechanism in which binding of one substrate tightens the binding of the other substrate to produce a productive ternary enzyme-substrate complex. In this work the molecular basis for this synergism is probed in crystallographic studies on ternary complexes in which the glucosyl component is substituted by the putative transition state analogue nojirimycin tetrazole, a compound which has been established previously as a transition state analogue inhibitor for a number of glycosidases. Kinetic studies with glycogen phosphorylase showed that nojirimycin tetrazole is a competitive inhibitor with respect to glucose 1-phosphate and uncompetitive with respect to phosphate. Ki values for the phosphorylase-AMP-glycogen complex and the phosphorylase-AMP-glycogen-phosphate complexes are 700 microM and 53 microM, respectively, indicating that by itself norjirimycin tetrazole has poor affinity for glycogen phosphorylase but that phosphate substantially improves the binding of norjirimycin tetrazole. X-ray crystallographic binding studies to 2.4 A resolution with T state phosphorylase b crystals showed that nojirimycin tetrazole binds at the catalytic site and promotes the binding of phosphate through direct interactions. Phosphate binding is accompanied by conformational changes that bring a crucial arginine (Arg569) into the catalytic site. The positions of the phosphate oxygens were definitively established in X-ray crystallographic binding experiments at 100 K to 1.7 A resolution using synchrotron radiation. X-ray crystallographic binding studies at 2.5 A resolution with R state glycogen phosphorylase crystals showed that the protein atoms and water molecules in contact with the nojirimycin tetrazole and the phosphate are similar to those in the T state. In both T and R states the phosphate ion is within hydrogen-bonding distance of the cofactor pyridoxal 5'-phosphate group and in ionic contact with the N-1 atom of the tetrazole ring. The results are consistent with previous time-resolved structural studies on complexes with heptenitol and phosphate. The structural and kinetic results suggest that nojirimycin tetrazole in combination with phosphate exhibits properties consistent with a transition state analogue and demonstrate how one promotes the binding of the other.


    Related Citations: 
    • Synthesis of a Glucose Derived Tetrazole as a New Beta-Glucosidase Inhibitor
      Ermert, P., Vasella, A.T.
      (1991) Helv Chim Acta 74: 2043
    • The Allosteric Transition of Glycogen Phosphorylase
      Barford, D., Johnson, L.N.
      (1989) Nature 340: 609

    Organizational Affiliation

    Laboratory of Molecular Biophysics, University of Oxford, UK.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
GLYCOGEN PHOSPHORYLASEA, B, C, D842Oryctolagus cuniculusMutation(s): 0 
Gene Names: PYGM
EC: 2.4.1.1
UniProt
Find proteins for P00489 (Oryctolagus cuniculus)
Explore P00489 
Go to UniProtKB:  P00489
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00489
Protein Feature View
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  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
NTZ Binding MOAD:  1NOI Ki: 7.00e+5 (nM) from 1 assay(s)
PDBBind:  1NOI Ki: 7.00e+5 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.171 
  • R-Value Observed: 0.171 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 119α = 90
b = 190β = 109.35
c = 88.2γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1996-08-01
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance