1SM9

Crystal Structure Of An Engineered K274RN276D Double Mutant of Xylose Reductase From Candida Tenuis Optimized To Utilize NAD


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.194 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

The coenzyme specificity of Candida tenuis xylose reductase (AKR2B5) explored by site-directed mutagenesis and X-ray crystallography.

Petschacher, B.Leitgeb, S.Kavanagh, K.L.Wilson, D.K.Nidetzky, B.

(2005) Biochem.J. 385: 75-83

  • DOI: 10.1042/BJ20040363

  • PubMed Abstract: 
  • CtXR (xylose reductase from the yeast Candida tenuis; AKR2B5) can utilize NADPH or NADH as co-substrate for the reduction of D-xylose into xylitol, NADPH being preferred approx. 33-fold. X-ray structures of CtXR bound to NADP+ and NAD+ have revealed ...

    CtXR (xylose reductase from the yeast Candida tenuis; AKR2B5) can utilize NADPH or NADH as co-substrate for the reduction of D-xylose into xylitol, NADPH being preferred approx. 33-fold. X-ray structures of CtXR bound to NADP+ and NAD+ have revealed two different protein conformations capable of accommodating the presence or absence of the coenzyme 2'-phosphate group. Here we have used site-directed mutagenesis to replace interactions specific to the enzyme-NADP+ complex with the aim of engineering the co-substrate-dependent conformational switch towards improved NADH selectivity. Purified single-site mutants K274R (Lys274-->Arg), K274M, K274G, S275A, N276D, R280H and the double mutant K274R-N276D were characterized by steady-state kinetic analysis of enzymic D-xylose reductions with NADH and NADPH at 25 degrees C (pH 7.0). The results reveal between 2- and 193-fold increases in NADH versus NADPH selectivity in the mutants, compared with the wild-type, with only modest alterations of the original NADH-linked xylose specificity and catalytic-centre activity. Catalytic reaction profile analysis demonstrated that all mutations produced parallel effects of similar magnitude on ground-state binding of coenzyme and transition state stabilization. The crystal structure of the double mutant showing the best improvement of coenzyme selectivity versus wild-type and exhibiting a 5-fold preference for NADH over NADPH was determined in a binary complex with NAD+ at 2.2 A resolution.


    Organizational Affiliation

    Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12/I, A-8010 Graz, Austria.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
xylose reductase
A, B, C, D
322Candida tenuisMutation(s): 2 
Gene Names: XYL1 (XYLR)
EC: 1.1.1.307
Find proteins for O74237 (Candida tenuis)
Go to UniProtKB:  O74237
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAD
Query on NAD

Download SDF File 
Download CCD File 
A, B, C, D
NICOTINAMIDE-ADENINE-DINUCLEOTIDE
C21 H27 N7 O14 P2
BAWFJGJZGIEFAR-NNYOXOHSSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.194 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 180.740α = 90.00
b = 128.190β = 90.43
c = 79.670γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
CNSphasing
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-12-21
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2011-11-16
    Type: Atomic model
  • Version 1.4: 2017-10-11
    Type: Refinement description