1XG4

Crystal Structure of the C123S 2-Methylisocitrate Lyase Mutant from Escherichia coli in complex with the inhibitor isocitrate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.201 
  • R-Value Work: 0.181 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal Structures of 2-Methylisocitrate Lyase in Complex with Product and with Isocitrate Inhibitor Provide Insight into Lyase Substrate Specificity, Catalysis and Evolution

Liu, S.Lu, Z.Han, Y.Melamud, E.Dunaway-Mariano, D.Herzberg, O.

(2005) Biochemistry 44: 2949-2962

  • DOI: 10.1021/bi0479712
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Two crystal structures of the C123S mutant of 2-methylisocitrate lyase have been determined, one with the bound reaction products, Mg(2+)-pyruvate and succinate, and the second with a bound Mg(2+)-(2R,3S)-isocitrate inhibitor. Comparison with the str ...

    Two crystal structures of the C123S mutant of 2-methylisocitrate lyase have been determined, one with the bound reaction products, Mg(2+)-pyruvate and succinate, and the second with a bound Mg(2+)-(2R,3S)-isocitrate inhibitor. Comparison with the structure of the wild-type enzyme in the unbound state reveals that the enzyme undergoes a conformational transition that sequesters the ligand from solvent, as previously observed for two other enzyme superfamily members, isocitrate lyase and phosphoenolpyruvate mutase. The binding modes reveal the determinants of substrate specificity and stereoselectivity, and the stringent specificity is verified in solution using various potential substrates. A model of bound 2-methylisocitrate has been developed based on the experimentally determined structures. We propose a catalytic mechanism involving an alpha-carboxy-carbanion intermediate/transition state, which is consistent with previous stereochemical experiments showing inversion of configuration at the C(3) of 2-methylisocitrate. Structure-based sequence analysis and phylogenic tree construction reveal determinants of substrate specificity, highlight nodes of divergence of families, and predict enzyme families with new functions.


    Organizational Affiliation

    Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Probable methylisocitrate lyase
A, B, C, D
295Escherichia coli (strain K12)Mutation(s): 1 
Gene Names: prpB (yahQ)
EC: 4.1.3.30
Find proteins for P77541 (Escherichia coli (strain K12))
Go to UniProtKB:  P77541
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MG
Query on MG

Download SDF File 
Download CCD File 
A, B, D
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
ICT
Query on ICT

Download SDF File 
Download CCD File 
A, B, D
ISOCITRIC ACID
C6 H8 O7
ODBLHEXUDAPZAU-ZAFYKAAXSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.201 
  • R-Value Work: 0.181 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 159.061α = 90.00
b = 84.561β = 108.15
c = 99.756γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
AMoREphasing
SCALEPACKdata scaling
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-03-01
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance