3PWA

Structure of C126A mutant of Plasmodium falciparum triosephosphate isomerase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.04 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.186 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Probing the role of the fully conserved Cys126 in triosephosphate isomerase by site-specific mutagenesis--distal effects on dimer stability.

Samanta, M.Banerjee, M.Murthy, M.R.Balaram, H.Balaram, P.

(2011) Febs J. 278: 1932-1943

  • DOI: 10.1111/j.1742-4658.2011.08110.x
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Cys126 is a completely conserved residue in triosephosphate isomerase that is proximal to the active site but has been ascribed no specific role in catalysis. A previous study of the C126S and C126A mutants of yeast TIM reported substantial catalytic ...

    Cys126 is a completely conserved residue in triosephosphate isomerase that is proximal to the active site but has been ascribed no specific role in catalysis. A previous study of the C126S and C126A mutants of yeast TIM reported substantial catalytic activity for the mutant enzymes, leading to the suggestion that this residue is implicated in folding and stability [Gonzalez-Mondragon E et al. (2004) Biochemistry 43, 3255-3263]. We re-examined the role of Cys126 with the Plasmodium falciparum enzyme as a model. Five mutants, C126S, C126A, C126V, C126M, and C126T, were characterized. Crystal structures of the 3-phosphoglycolate-bound C126S mutant and the unliganded forms of the C126S and C126A mutants were determined at a resolution of 1.7-2.1 Å. Kinetic studies revealed an approximately five-fold drop in k(cat) for the C126S and C126A mutants, whereas an approximately 10-fold drop was observed for the other three mutants. At ambient temperature, the wild-type enzyme and all five mutants showed no concentration dependence of activity. At higher temperatures (> 40 °C), the mutants showed a significant concentration dependence, with a dramatic loss in activity below 15 μM. The mutants also had diminished thermal stability at low concentration, as monitored by far-UV CD. These results suggest that Cys126 contributes to the stability of the dimer interface through a network of interactions involving His95, Glu97, and Arg98, which form direct contacts across the dimer interface.


    Organizational Affiliation

    Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Triosephosphate isomerase
A, B
248Plasmodium falciparumMutation(s): 1 
Gene Names: TPI
EC: 5.3.1.1
Find proteins for Q07412 (Plasmodium falciparum)
Go to UniProtKB:  Q07412
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
ACT
Query on ACT

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Download CCD File 
A, B
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
EDO
Query on EDO

Download SDF File 
Download CCD File 
A
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.04 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.186 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 51.010α = 90.00
b = 175.360β = 90.00
c = 54.170γ = 90.00
Software Package:
Software NamePurpose
MAR345dtbdata collection
PHASERphasing
SCALAdata scaling
REFMACrefinement
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-04-27
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2013-08-28
    Type: Database references