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Overview for MACiE Entry M0325

Version history

General Information

EC Number: 5.4.4.2 (A member of the Isomerases, Intramolecular transferases, Transferring hydroxy groups)

Enzyme Name: isochorismate synthase

Biological Species: Escherichia coli (Bacteria)

Catalytic Chain UniprotKB Accession Codes:

  • P38051 - Menaquinone-specific isochorismate synthase

Representative PDB Code: 2eua - STRUCTURE AND MECHANISM OF MENF, THE MENAQUINONE-SPECIFICISOCHORISMATE SYNTHASE FROM ESCHERICHIA COLI (Resolution = 2.50 Å).

Catalytic CATH Codes:

  • Unassigned Domain

Display structure information

Overall Reaction:

Image of chorismate

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Image of isochorismate

chorismate
C00251
CHEBI:29748
isochorismate
C00885
CHEBI:29780

Overall Comment: Mg(II) was thought to activate the nucleophilic water molecule, but instead a related crystal structure (IRP9) has shown the metal to be incorrectly positioned for this role, and instead is thought to aid substrate binding within the active site. This is in agreement with the orientation of active site residues in the crystal structure reported here [1].


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Stepwise Description of the Reaction

Step 1The catalytic base, Lys190, is position to activate water towards nucleophilic attack at the C6 position, initiating rearrangement of the ring conjugation, and eliminating water from the C4 position.
Step 2It is inferred that the active site is regenerated by the transmission of a proton between the catalytic acid Glu240 and the catalytic base Lys190.

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Catalytic Residues Involved

Type Number Chain Location of Function
Lys 420 A Side Chain
Glu 416 A Side Chain
Glu 284 A Side Chain
Lys 190 A Side Chain
Glu 240 A Side Chain

Metal Cofactors for M0325

Type Het group Number Chain
magnesium No Available PDB Information

References

  1. S. Kolappan et al. (2007), Biochemistry, 46, 946-952. Lysine 190 is the catalytic base in MenF, the menaquinone-specific isochorismate synthase from Escherichia coli: implications for an enzyme family.
    Medline: 17240978
  2. S. Sridharan et al. (2010), J. Mol. Biol., 397, 290-300. 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.
    Medline: 20079748

Homologue information for M0325 (2eua)

CSA Homologues

MACiE Homologues (within the PDB)

MACiE Homologues (within UniprotKB/SwissProt)


Links to this entry in other databases

Link to EC-PDB-SUM Link to PDB-SUM Link to RCSB PDB Link to PDBe Link to CSA
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isochorismate synthase activity (molecular function)
biosynthetic process (biological process)
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