2X7J

Structure of the menaquinone biosynthesis protein MenD from Bacillus subtilis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.172 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure and Reactivity of Bacillus Subtilis Mend Catalyzing the First Committed Step in Menaquinone Biosynthesis.

Dawson, A.Chen, M.Fyfe, P.K.Guo, Z.Hunter, W.N.

(2010) J.Mol.Biol. 401: 253

  • DOI: 10.1016/j.jmb.2010.06.025

  • PubMed Abstract: 
  • The first committed step in the classical biosynthetic route to menaquinone (vitamin K(2)) is a Stetter-like conjugate addition of alpha-ketoglutarate with isochorismate. This reaction is catalyzed by the thiamine diphosphate and metal-ion-dependent ...

    The first committed step in the classical biosynthetic route to menaquinone (vitamin K(2)) is a Stetter-like conjugate addition of alpha-ketoglutarate with isochorismate. This reaction is catalyzed by the thiamine diphosphate and metal-ion-dependent 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexadiene-1-carboxylate synthase (MenD). The medium-resolution (2.35 A) crystal structure of Bacillus subtilis MenD with cofactor and Mn(2+) has been determined. Based on structure-sequence comparisons and modeling, a two-stage mechanism that is primarily driven by the chemical properties of the cofactor is proposed. Hypotheses for the molecular determinants of substrate recognition were formulated. Five basic residues (Arg32, Arg106, Arg409, Arg428, and Lys299) are postulated to interact with carboxylate and hydroxyl groups to align substrates for catalysis in combination with a cluster of non-polar residues (Ile489, Phe490, and Leu493) on one side of the active site. The powerful combination of site-directed mutagenesis, where each of the eight residues is replaced by alanine, and steady-state kinetic measurements has been exploited to address these hypotheses. Arg409 plays a significant role in binding both substrates while Arg428 contributes mainly to binding of alpha-ketoglutarate. Arg32 and in particular Arg106 are critical for recognition of isochorismate. Mutagenesis of Phe490 and Ile489 has the most profound influence on catalytic efficiency, indicating that these two residues are important for binding of isochorismate and for stabilizing the cofactor position. These data allow for a detailed description of the structure-reactivity relationship that governs MenD function and refinement of the model for the catalytic intermediate that supports the Stetter-like conjugate addition.


    Organizational Affiliation

    Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
2-SUCCINYL-5-ENOLPYRUVYL-6-HYDROXY-3-CYCLOHEXENE -1-CARBOXYLATE SYNTHASE
A, B, C, D
604Bacillus subtilis (strain 168)Mutation(s): 0 
Gene Names: menD
EC: 2.2.1.9
Find proteins for P23970 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P23970
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
TPP
Query on TPP

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Download CCD File 
A, B, C, D
THIAMINE DIPHOSPHATE
C12 H19 N4 O7 P2 S
AYEKOFBPNLCAJY-UHFFFAOYSA-O
 Ligand Interaction
MN
Query on MN

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Download CCD File 
A, B, C, D
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
NA
Query on NA

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Download CCD File 
A, B, C, D
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

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Download CCD File 
A, B, C, D
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
EDO
Query on EDO

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.172 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 100.180α = 90.00
b = 152.990β = 90.00
c = 158.499γ = 90.00
Software Package:
Software NamePurpose
XDSdata reduction
SCALAdata scaling
SOLVEphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-07-14
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance