1B8O

PURINE NUCLEOSIDE PHOSPHORYLASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.184 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 2.1 of the entry. See complete history


Literature

Transition state structure of purine nucleoside phosphorylase and principles of atomic motion in enzymatic catalysis.

Fedorov, A.Shi, W.Kicska, G.Fedorov, E.Tyler, P.C.Furneaux, R.H.Hanson, J.C.Gainsford, G.J.Larese, J.Z.Schramm, V.L.Almo, S.C.

(2001) Biochemistry 40: 853-860

  • DOI: https://doi.org/10.1021/bi002499f
  • Primary Citation of Related Structures:  
    1B8O

  • PubMed Abstract: 

    Immucillin-H [ImmH; (1S)-1-(9-deazahypoxanthin-9-yl)-1,4-dideoxy-1,4-imino-D-ribitol] is a 23 pM inhibitor of bovine purine nucleoside phosphorylase (PNP) specifically designed as a transition state mimic [Miles, R. W., Tyler, P. C., Furneaux, R. H., Bagdassarian, C. K., and Schramm, V. L. (1998) Biochemistry 37, 8615-8621]. Cocrystals of PNP and the inhibitor are used to provide structural information for each step through the reaction coordinate of PNP. The X-ray crystal structure of free ImmH was solved at 0.9 A resolution, and a complex of PNP.ImmH.PO(4) was solved at 1.5 A resolution. These structures are compared to previously reported complexes of PNP with substrate and product analogues in the catalytic sites and with the experimentally determined transition state structure. Upon binding, ImmH is distorted to a conformation favoring ribosyl oxocarbenium ion formation. Ribosyl destabilization and transition state stabilization of the ribosyl oxocarbenium ion occur from neighboring group interactions with the phosphate anion and the 5'-hydroxyl of the ribosyl group. Leaving group activation of hypoxanthine involves hydrogen bonds to O6, N1, and N7 of the purine ring. Ordered water molecules provide a proton transfer bridge to O6 and N7 and permit reversible formation of these hydrogen bonds. Contacts between PNP and catalytic site ligands are shorter in the transition state analogue complex of PNP.ImmH.PO(4) than in the Michaelis complexes of PNP.inosine.SO(4) or PNP.hypoxanthine.ribose 1-PO(4). Reaction coordinate motion is dominated by translation of the carbon 1' of ribose between relatively fixed phosphate and purine groups. Purine and pyrimidine phosphoribosyltransferases and nucleoside N-ribosyl hydrolases appear to operate by a similar mechanism.


  • Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PURINE NUCLEOSIDE PHOSPHORYLASE284Bos taurusMutation(s): 0 
EC: 2.4.2.1
UniProt
Find proteins for P55859 (Bos taurus)
Explore P55859 
Go to UniProtKB:  P55859
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP55859
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
IMH
Query on IMH

Download Ideal Coordinates CCD File 
D [auth A]1,4-DIDEOXY-4-AZA-1-(S)-(9-DEAZAHYPOXANTHIN-9-YL)-D-RIBITOL
C11 H14 N4 O4
IWKXDMQDITUYRK-KUBHLMPHSA-N
PO4
Query on PO4

Download Ideal Coordinates CCD File 
C [auth A]PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
MG
Query on MG

Download Ideal Coordinates CCD File 
B [auth A]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
Binding Affinity Annotations 
IDSourceBinding Affinity
IMH BindingDB:  1B8O Ki: min: 0.06, max: 72 (nM) from 6 assay(s)
Kd: min: 0.02, max: 0.06 (nM) from 3 assay(s)
IC50: min: 0.06, max: 100 (nM) from 3 assay(s)
ΔH: -3.50e+1 (kJ/mol) from 1 assay(s)
ΔG: -4.56e+1 (kJ/mol) from 1 assay(s)
PDBBind:  1B8O Ki: 0.02 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.184 
  • Space Group: P 21 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 92.683α = 90
b = 92.683β = 90
c = 92.683γ = 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: 1999-02-08
    Type: Initial release
  • Version 1.1: 2008-04-26
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2019-10-30
    Changes: Data collection, Database references
  • Version 2.0: 2022-10-05
    Changes: Atomic model, Database references, Derived calculations, Structure summary
  • Version 2.1: 2023-09-20
    Changes: Data collection, Refinement description