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 
  • R-Value Observed: 0.175 

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
  • Primary Citation of Related Structures:  
    2X7J

  • 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:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
2-SUCCINYL-5-ENOLPYRUVYL-6-HYDROXY-3-CYCLOHEXENE -1-CARBOXYLATE SYNTHASEABCD604Bacillus subtilisMutation(s): 0 
EC: 2.2.1.9
Find proteins for P23970 (Bacillus subtilis (strain 168))
Explore P23970 
Go to UniProtKB:  P23970
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
TPP
Query on TPP

Download CCD File 
A, B, C, D
THIAMINE DIPHOSPHATE
C12 H19 N4 O7 P2 S
AYEKOFBPNLCAJY-UHFFFAOYSA-O
 Ligand Interaction
SO4
Query on SO4

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

Download CCD File 
A, B, C, D
1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
MN
Query on MN

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

Download CCD File 
A, B, C, D
SODIUM ION
Na
FKNQFGJONOIPTF-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 
  • R-Value Observed: 0.175 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 100.18α = 90
b = 152.99β = 90
c = 158.499γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
SCALAdata scaling
SOLVEphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

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