3ZKY

Isopenicillin N synthase with substrate analogue AhCmC


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.182 
  • R-Value Work: 0.165 
  • R-Value Observed: 0.165 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

The Interaction of Isopenicillin N Synthase with Homologated Substrate Analogues Delta-(L-Alpha-Aminoadipoyl)-L-Homocysteinyl-D-Xaa Characterised by Protein Crystallography.

Daruzzaman, A.Clifton, I.J.Adlington, R.M.Baldwin, J.E.Rutledge, P.J.

(2013) Chembiochem 14: 599

  • DOI: https://doi.org/10.1002/cbic.201200728
  • Primary Citation of Related Structures:  
    3ZKU, 3ZKY

  • PubMed Abstract: 

    Isopenicillin N synthase (IPNS) converts the linear tripeptide δ-(L-α-aminoadipoyl)-L-cysteinyl-D-valine (ACV) into bicyclic isopenicillin N (IPN) in the central step in the biosynthesis of penicillin and cephalosporin antibiotics. Solution-phase incubation experiments have shown that IPNS turns over analogues with a diverse range of side chains in the third (valinyl) position of the substrate, but copes less well with changes in the second (cysteinyl) residue. IPNS thus converts the homologated tripeptides δ-(L-α-aminoadipoyl)-L-homocysteinyl-D-valine (AhCV) and δ-(L-α-aminoadipoyl)-L-homocysteinyl-D-allylglycine (AhCaG) into monocyclic hydroxy-lactam products; this suggests that the additional methylene unit in these substrates induces conformational changes that preclude second ring closure after initial lactam formation. To investigate this and solution-phase results with other tripeptides δ-(L-α-aminoadipoyl)-L-homocysteinyl-D-Xaa, we have crystallised AhCV and δ-(L-α-aminoadipoyl)-L-homocysteinyl-D-S-methylcysteine (AhCmC) with IPNS and solved crystal structures for the resulting complexes. The IPNS:Fe(II):AhCV complex shows diffuse electron density for several regions of the substrate, revealing considerable conformational freedom within the active site. The substrate is more clearly resolved in the IPNS:Fe(II):AhCmC complex, by virtue of thioether coordination to iron. AhCmC occupies two distinct conformations, both distorted relative to the natural substrate ACV, in order to accommodate the extra methylene group in the second residue. Attempts to turn these substrates over within crystalline IPNS using hyperbaric oxygenation give rise to product mixtures.


  • Organizational Affiliation

    Chemistry Research Laboratory, University of Oxford, Mansfield Rd, Oxford, OX1 3TA, UK.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ISOPENICILLIN N SYNTHASE331Aspergillus nidulans FGSC A4Mutation(s): 0 
EC: 1.21.3.1
UniProt
Find proteins for P05326 (Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139))
Explore P05326 
Go to UniProtKB:  P05326
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP05326
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.182 
  • R-Value Work: 0.165 
  • R-Value Observed: 0.165 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 46.705α = 90
b = 71.29β = 90
c = 100.92γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-03-20
    Type: Initial release
  • Version 1.1: 2013-04-10
    Changes: Database references
  • Version 1.2: 2017-07-05
    Changes: Refinement description
  • Version 1.3: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description
  • Version 1.4: 2024-05-08
    Changes: Source and taxonomy