4NU5

Crystal Structure of PTDH R301A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.184 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Chemical rescue and inhibition studies to determine the role of arg301 in phosphite dehydrogenase.

Hung, J.E.Fogle, E.J.Garg, N.Chekan, J.R.Nair, S.K.van der Donk, W.A.

(2014) Plos One 9: e87134-e87134

  • DOI: 10.1371/journal.pone.0087134
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Phosphite dehydrogenase (PTDH) catalyzes the NAD(+)-dependent oxidation of phosphite to phosphate. This reaction requires the deprotonation of a water nucleophile for attack on phosphite. A crystal structure was recently solved that identified Arg301 ...

    Phosphite dehydrogenase (PTDH) catalyzes the NAD(+)-dependent oxidation of phosphite to phosphate. This reaction requires the deprotonation of a water nucleophile for attack on phosphite. A crystal structure was recently solved that identified Arg301 as a potential base given its proximity and orientation to the substrates and a water molecule within the active site. Mutants of this residue showed its importance for efficient catalysis, with about a 100-fold loss in k cat and substantially increased K m,phosphite for the Ala mutant (R301A). The 2.35 Å resolution crystal structure of the R301A mutant with NAD(+) bound shows that removal of the guanidine group renders the active site solvent exposed, suggesting the possibility of chemical rescue of activity. We show that the catalytic activity of this mutant is restored to near wild-type levels by the addition of exogenous guanidinium analogues; Brønsted analysis of the rates of chemical rescue suggests that protonation of the rescue reagent is complete in the transition state of the rate-limiting step. Kinetic isotope effects on the reaction in the presence of rescue agents show that hydride transfer remains at least partially rate-limiting, and inhibition experiments show that K i of sulfite with R301A is ∼400-fold increased compared to the parent enzyme, similar to the increase in K m for phosphite in this mutant. The results of our experiments indicate that Arg301 plays an important role in phosphite binding as well as catalysis, but that it is not likely to act as an active site base.


    Organizational Affiliation

    Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Phosphonate dehydrogenase
A, B
329Pseudomonas stutzeriMutation(s): 1 
Gene Names: ptxD
EC: 1.20.1.1
Find proteins for O69054 (Pseudomonas stutzeri)
Go to UniProtKB:  O69054
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAD
Query on NAD

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.184 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 116.486α = 90.00
b = 80.456β = 90.00
c = 81.966γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
HKL-3000data scaling
DENZOdata reduction
PDB_EXTRACTdata extraction
HKL-3000data reduction
PHASERphasing
SCALEPACKdata scaling
HKL-3000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-03-12
    Type: Initial release
  • Version 1.1: 2014-11-12
    Type: Structure summary
  • Version 1.2: 2017-11-22
    Type: Refinement description