2VCM

Isopenicillin N synthase with substrate analogue AsMCOV


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.166 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Studies on the Reaction of Isopenicillin N Synthase with a Sterically Demanding Depsipeptide Substrate Analogue.

Ge, W.Clifton, I.J.Howard-Jones, A.R.Stok, J.E.Adlington, R.M.Baldwin, J.E.Rutledge, P.J.

(2009) Chembiochem 10: 2025

  • DOI: 10.1002/cbic.200900080
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Isopenicillin N synthase (IPNS) is a nonheme iron(II)-dependent oxidase that catalyses the central step in penicillin biosynthesis, conversion of the tripeptide delta-L-alpha-aminoadipoyl-L-cysteinyl-D-valine (ACV) to isopenicillin N (IPN). This repo ...

    Isopenicillin N synthase (IPNS) is a nonheme iron(II)-dependent oxidase that catalyses the central step in penicillin biosynthesis, conversion of the tripeptide delta-L-alpha-aminoadipoyl-L-cysteinyl-D-valine (ACV) to isopenicillin N (IPN). This report describes mechanistic studies using the analogue delta-(L-alpha-aminoadipoyl)-(3S-methyl)-L-cysteine D-alpha-hydroxyisovaleryl ester (A(S)mCOV), designed to intercept the catalytic cycle at an early stage. A(S)mCOV incorporates two modifications from the natural substrate: the second and third residues are joined by an ester, so this analogue lacks the key amide of ACV and cannot form a beta-lactam; and the cysteinyl residue is substituted at its beta-carbon, bearing a (3S)-methyl group. It was anticipated that this methyl group will impinge directly on the site in which the co-substrate dioxygen binds. The novel depsipeptide A(S)mCOV was prepared in 13 steps and crystallised with IPNS anaerobically. The 1.65 A structure of the IPNS-Fe(II)-A(S)mCOV complex reveals that the additional beta-methyl group is not oriented directly into the oxygen binding site, but does increase steric demand in the active site and increases disorder in the position of the isovaleryl side chain. Crystals of IPNS-Fe(II)-A(S)mCOV were incubated with high-pressure oxygen gas, driving substrate turnover to a single product, an ene-thiol/C-hydroxylated depsipeptide. A mechanism is proposed for the reaction of A(S)mCOV with IPNS, linking this result to previous crystallographic studies with related depsipeptides and solution-phase experiments with cysteine-methylated tripeptides. This result demonstrates that a (3S)-methyl group at the substrate cysteinyl beta-carbon is not in itself a block to IPNS activity as previously proposed, and sheds further light on the steric complexities of IPNS catalysis.


    Organizational Affiliation

    Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA (UK).




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ISOPENICILLIN N SYNTHETASE
A
331Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139)Mutation(s): 0 
Gene Names: ipnA (ips)
EC: 1.21.3.1
Find proteins for P05326 (Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139))
Go to UniProtKB:  P05326
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
M11
Query on M11

Download SDF File 
Download CCD File 
A
N^6^-[(1R,2S)-1-({[(1R)-1-carboxy-2-methylpropyl]oxy}carbonyl)-2-sulfanylpropyl]-6-oxo-L-lysine
C15 H26 N2 O7 S
SEWFXDOLNMAGTP-FSZOTQKASA-N
 Ligand Interaction
FE2
Query on FE2

Download SDF File 
Download CCD File 
A
FE (II) ION
Fe
CWYNVVGOOAEACU-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.166 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 41.576α = 90.00
b = 75.353β = 90.00
c = 101.511γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
REFMACphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-11-04
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance