1A72

AN ACTIVE-SITE DOUBLE MUTANT (PHE93->TRP, VAL203->ALA) OF HORSE LIVER ALCOHOL DEHYDROGENASE IN COMPLEX WITH THE ISOSTERIC NAD ANALOG CPAD


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.300 
  • R-Value Work: 0.176 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Active site modifications in a double mutant of liver alcohol dehydrogenase: structural studies of two enzyme-ligand complexes.

Colby, T.D.Bahnson, B.J.Chin, J.K.Klinman, J.P.Goldstein, B.M.

(1998) Biochemistry 37: 9295-9304

  • DOI: 10.1021/bi973184b
  • Primary Citation of Related Structures:  1A71

  • PubMed Abstract: 
  • The oxidation of alcohol to aldehyde by horse liver alcohol dehydrogenase (LADH) requires the transfer of a hydride ion from the alcohol substrate to the cofactor nicotinamide adenine dinucleotide (NAD). A quantum mechanical tunneling contribution to ...

    The oxidation of alcohol to aldehyde by horse liver alcohol dehydrogenase (LADH) requires the transfer of a hydride ion from the alcohol substrate to the cofactor nicotinamide adenine dinucleotide (NAD). A quantum mechanical tunneling contribution to this hydride transfer step has been demonstrated in a number of LADH mutants designed to enhance or diminish this effect [Bahnson, B. J., et al. (1997) Proc. Natl. Acad. Sci. U.S.A. 94, 12797-12802]. The active site double mutant Phe93 --> Trp/Val203 --> Ala shows a 75-fold reduction in catalytic efficiency relative to that of the native enzyme, and reduced tunneling relative to that of either single mutant. We present here two crystal structures of the double mutant: a 2.0 A complex with NAD and the substrate analogue trifluoroethanol and a 2.6 A complex with the isosteric NAD analogue CPAD and ethanol. Changes at the active site observed in both complexes are consistent with reduced activity and tunneling. The NAD-trifluoroethanol complex crystallizes in the closed conformation characteristic of the active enzyme. However, the NAD nicotinamide ring rotates away from the substrate, toward the space vacated by replacement of Val203 with the smaller alanine. Replacement of Phe93 with the larger tryptophan also produces unfavorable steric contacts with the nicotinamide carboxamide group, potentially destabilizing hydrogen bonds required to maintain the closed conformation. These contacts are relieved in the second complex by rotation of the CPAD pyridine ring into an unusual syn orientation. The resulting loss of the carboxamide hydrogen bonds produces an open conformation characteristic of the apoenzyme.


    Related Citations: 
    • A Link between Protein Structure and Enzyme Catalyzed Hydrogen Tunneling
      Bahnson, B.J.,Colby, T.D.,Chin, J.K.,Goldstein, B.M.,Klinman, J.P.
      (1997) Proc.Natl.Acad.Sci.USA 94: 12797


    Organizational Affiliation

    Department of Biochemistry and Biophysics, University of Rochester Medical Center, New York 14642, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HORSE LIVER ALCOHOL DEHYDROGENASE
A
374Equus caballusEC: 1.1.1.1
Find proteins for P00327 (Equus caballus)
Go to UniProtKB:  P00327
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
PAD
Query on PAD

Download SDF File 
Download CCD File 
A
5-BETA-D-RIBOFURANOSYLPICOLINAMIDE ADENINE-DINUCLEOTIDE
CPAD
C21 H27 N7 O14 P2
LFERELMXERXKKQ-KMXXXSRASA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.300 
  • R-Value Work: 0.176 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 55.500α = 90.00
b = 74.200β = 90.00
c = 179.200γ = 90.00
Software Package:
Software NamePurpose
XDSdata reduction
X-GENdata scaling
X-PLORrefinement
X-PLORphasing
X-PLORmodel building

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1998-06-17
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance