4J1W

Crystal Structure of Fe(II)-HppE with alternative substrate (R)-1-HPP

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.72 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.242 

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This is version 1.1 of the entry. See complete history. 


Literature

Mechanistic studies of an unprecedented enzyme-catalysed 1,2-phosphono-migration reaction.

Chang, W.C., Dey, M., Liu, P., Mansoorabadi, S.O., Moon, S.J., Zhao, Z.K., Drennan, C.L., Liu, H.W.

(2013) Nature 496: 114-118

  • DOI: 10.1038/nature11998
  • Primary Citation of Related Structures:  
    4J1W, 4J1X

  • PubMed Abstract: 

    • (S)-2-hydroxypropylphosphonate ((S)-2-HPP) epoxidase (HppE) is a mononuclear non-haem-iron-dependent enzyme responsible for the final step in the biosynthesis of the clinically useful antibiotic fosfomycin. Enzymes of this class typically catalyse oxygenation reactions that proceed via the formation of substrate radical intermediates ...

    (S)-2-hydroxypropylphosphonate ((S)-2-HPP) epoxidase (HppE) is a mononuclear non-haem-iron-dependent enzyme responsible for the final step in the biosynthesis of the clinically useful antibiotic fosfomycin. Enzymes of this class typically catalyse oxygenation reactions that proceed via the formation of substrate radical intermediates. By contrast, HppE catalyses an unusual dehydrogenation reaction while converting the secondary alcohol of (S)-2-HPP to the epoxide ring of fosfomycin. Here we show that HppE also catalyses a biologically unprecedented 1,2-phosphono migration with the alternative substrate (R)-1-HPP. This transformation probably involves an intermediary carbocation, based on observations with additional substrate analogues, such as (1R)-1-hydroxyl-2-aminopropylphosphonate, and model reactions for both radical- and carbocation-mediated migration. The ability of HppE to catalyse distinct reactions depending on the regio- and stereochemical properties of the substrate is given a structural basis using X-ray crystallography. These results provide compelling evidence for the formation of a substrate-derived cation intermediate in the catalytic cycle of a mononuclear non-haem-iron-dependent enzyme. The underlying chemistry of this unusual phosphono migration may represent a new paradigm for the in vivo construction of phosphonate-containing natural products that can be exploited for the preparation of new phosphonate derivatives.

    Organizational Affiliation: 

    Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
EpoxidaseA, B, C198Streptomyces wedmorensisMutation(s): 0 
Gene Names: fom4, hppE
EC: 1.11.1.23
UniProt
Find proteins for Q56185 (Streptomyces wedmorensis)
Explore Q56185 
Go to UniProtKB:  Q56185
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ56185
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.72 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.242 
  • Space Group: P 42 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 111.489α = 90
b = 111.489β = 90
c = 151.484γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
CNSrefinement
HKL-2000data reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

  • Deposited Date: 2013-02-03 
  • Released Date: 2013-04-03 
    • Deposition Author(s): Drennan, C.L., Dey, M.

Revision History  (Full details and data files)

  • Version 1.0: 2013-04-03
    Type: Initial release
  • Version 1.1: 2013-04-17
    Changes: Database references