1AI3

ORBITAL STEERING IN THE CATALYTIC POWER OF ENZYMES: SMALL STRUCTURAL CHANGES WITH LARGE CATALYTIC CONSEQUENCES


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.188 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Orbital steering in the catalytic power of enzymes: small structural changes with large catalytic consequences.

Mesecar, A.D.Stoddard, B.L.Koshland Jr., D.E.

(1997) Science 277: 202-206

  • DOI: 10.1126/science.277.5323.202
  • Primary Citation of Related Structures:  
    1AI2, 1AI3

  • PubMed Abstract: 
  • Small structural perturbations in the enzyme isocitrate dehydrogenase (IDH) were made in order to evaluate the contribution of precise substrate alignment to the catalytic power of an enzyme. The reaction trajectory of IDH was modified (i) after the adenine moiety of nicotinamide adenine dinucleotide phosphate was changed to hypoxanthine (the 6-amino was changed to 6-hydroxyl), and (ii) by replacing Mg2+, which has six coordinating ligands, with Ca2+, which has eight coordinating ligands ...

    Small structural perturbations in the enzyme isocitrate dehydrogenase (IDH) were made in order to evaluate the contribution of precise substrate alignment to the catalytic power of an enzyme. The reaction trajectory of IDH was modified (i) after the adenine moiety of nicotinamide adenine dinucleotide phosphate was changed to hypoxanthine (the 6-amino was changed to 6-hydroxyl), and (ii) by replacing Mg2+, which has six coordinating ligands, with Ca2+, which has eight coordinating ligands. Both changes make large (10(-3) to 10(-5)) changes in the reaction velocity but only small changes in the orientation of the substrates (both distance and angle) as revealed by cryocrystallographic trapping of active IDH complexes. The results provide evidence that orbital overlap produced by optimal orientation of reacting orbitals plays a major quantitative role in the catalytic power of enzymes.


    Related Citations: 
    • Determinants of Cofactor Specificity in Isocitrate Dehydrogenase: Structure of an Engineered Nadp+--> Nad+ Specificity-Reversal Mutant
      Hurley, J.H., Chen, R., Dean, A.M.
      (1996) Biochemistry 35: 5670
    • Structure of Isocitrate Dehydrogenase with Isocitrate, Nicotinamide Adenine Dinucleotide Phosphate, and Calcium at 2.5-A Resolution: A Pseudo-Michaelis Ternary Complex
      Stoddard, B.L., Dean, A., Koshland Junior, D.E.
      (1993) Biochemistry 32: 9310

    Organizational Affiliation

    Department of Molecular and Cell Biology, Stanley Hall, University of California, Berkeley, CA 94720, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ISOCITRATE DEHYDROGENASEA416Escherichia coliMutation(s): 0 
EC: 1.1.1.42
UniProt
Find proteins for P08200 (Escherichia coli (strain K12))
Explore P08200 
Go to UniProtKB:  P08200
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NDO (Subject of Investigation/LOI)
Query on NDO

Download Ideal Coordinates CCD File 
B [auth A]NICOTINAMIDE-(6-DEAMINO-6-HYDROXY-ADENINE)-DINUCLEOTIDE PHOSPHATE
C21 H27 N6 O18 P3
WKSUSMNNBQFESD-NNYOXOHSSA-N
 Ligand Interaction
ICT (Subject of Investigation/LOI)
Query on ICT

Download Ideal Coordinates CCD File 
C [auth A]ISOCITRIC ACID
C6 H8 O7
ODBLHEXUDAPZAU-ZAFYKAAXSA-N
 Ligand Interaction
MG
Query on MG

Download Ideal Coordinates CCD File 
D [auth A]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Binding Affinity Annotations 
IDSourceBinding Affinity
NDO Binding MOAD:  1AI3 Ki: 4.03e+5 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.188 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 102.4α = 90
b = 102.4β = 90
c = 150.7γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling
X-PLORphasing

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-11-12
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2011-11-02
    Changes: Non-polymer description