3HWO

Crystal structure of Escherichia coli enterobactin-specific isochorismate synthase EntC in complex with isochorismate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.200 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal Structure of Escherichia coli Enterobactin-specific Isochorismate Synthase (EntC) Bound to its Reaction Product Isochorismate: Implications for the Enzyme Mechanism and Differential Activity of Chorismate-utilizing Enzymes

Sridharan, S.Howard, N.Kerbarh, O.Blaszczyk, M.Abell, C.Blundell, T.L.

(2010) J.Mol.Biol. 397: 290-300

  • DOI: 10.1016/j.jmb.2010.01.019
  • Also Cited By: 5JZD

  • PubMed Abstract: 
  • EntC, one of two isochorismate synthases in Escherichia coli, is specific to the biosynthesis of the siderophore enterobactin. Here, we report the crystal structure of EntC in complex with isochorismate and Mg(2+)at 2.3 A resolution, the first struct ...

    EntC, one of two isochorismate synthases in Escherichia coli, is specific to the biosynthesis of the siderophore enterobactin. Here, we report the crystal structure of EntC in complex with isochorismate and Mg(2+)at 2.3 A resolution, the first structure of a chorismate-utilizing enzyme with a non-aromatic reaction product. EntC exhibits a complex alpha+beta fold like the other chorismate-utilizing enzymes, such as salicylate synthase and anthranilate synthase. Comparison of active site structures allowed the identification of several residues, not discussed previously, that might be important for the isochorismate activity of the EntC. Although EntC, MenF and Irp9 all convert chorismate to isochorismate, only Irp9 subsequently exhibits isochorismate pyruvate lyase activity resulting in the formation of salicylate and pyruvate as the reaction products. With a view to understanding the roles of these amino acid residues in the conversion of chorismate to isochorismate and to obtaining clues about the pyruvate lyase activity of Irp9, several mutants of EntC were generated in which the selected residues in EntC were substituted for those of Irp9: these included A303T, L304A, F327Y, I346L and F359Q mutations. Biochemical analysis of these mutants indicated that the side chain of A303 in EntC may be crucial in the orientation of the carbonyl to allow formation of a hydrogen bond with isochorismate. Some mutations, such as L304A and F359Q, give rise to a loss of catalytic activity, whereas others, such as F327Y and I346L, show that subtle changes in the otherwise closely similar active sites influence activity. We did not find a combination of these residues that conferred pyruvate lyase activity.


    Organizational Affiliation

    Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Isochorismate synthase entC
A, B
394Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: entC
EC: 5.4.4.2
Find proteins for P0AEJ2 (Escherichia coli (strain K12))
Go to UniProtKB:  P0AEJ2
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MG
Query on MG

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

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Download CCD File 
A, B
(5S,6S)-5-[(1-carboxyethenyl)oxy]-6-hydroxycyclohexa-1,3-diene-1-carboxylic acid
ISOCHORISMIC ACID
C10 H10 O6
NTGWPRCCOQCMGE-YUMQZZPRSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.200 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 62.469α = 90.00
b = 104.795β = 90.00
c = 140.014γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
SCALEPACKdata scaling
ADSCdata collection
DENZOdata reduction
SHARPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-02-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2011-09-14
    Type: Non-polymer description