4EB3

Crystal structure of IspH in complex with iso-HMBPP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Are free radicals involved in IspH catalysis? An EPR and crystallographic investigation.

Wang, W.Wang, K.Span, I.Jauch, J.Bacher, A.Groll, M.Oldfield, E.

(2012) J.Am.Chem.Soc. 134: 11225-11234

  • DOI: 10.1021/ja303445z

  • PubMed Abstract: 
  • The [4Fe-4S] protein IspH in the methylerythritol phosphate isoprenoid biosynthesis pathway is an important anti-infective drug target, but its mechanism of action is still the subject of debate. Here, by using electron paramagnetic resonance (EPR) s ...

    The [4Fe-4S] protein IspH in the methylerythritol phosphate isoprenoid biosynthesis pathway is an important anti-infective drug target, but its mechanism of action is still the subject of debate. Here, by using electron paramagnetic resonance (EPR) spectroscopy and (2)H, (17)O, and (57)Fe isotopic labeling, we have characterized and assigned two key reaction intermediates in IspH catalysis. The results are consistent with the bioorganometallic mechanism proposed earlier, and the mechanism is proposed to have similarities to that of ferredoxin, thioredoxin reductase, in that one electron is transferred to the [4Fe-4S](2+) cluster, which then performs a formal two-electron reduction of its substrate, generating an oxidized high potential iron-sulfur protein (HiPIP)-like intermediate. The two paramagnetic reaction intermediates observed correspond to the two intermediates proposed in the bioorganometallic mechanism: the early π-complex in which the substrate's 3-CH(2)OH group has rotated away from the reduced iron-sulfur cluster, and the next, η(3)-allyl complex formed after dehydroxylation. No free radical intermediates are observed, and the two paramagnetic intermediates observed do not fit in a Birch reduction-like or ferraoxetane mechanism. Additionally, we show by using EPR spectroscopy and X-ray crystallography that two substrate analogues (4 and 5) follow the same reaction mechanism.


    Organizational Affiliation

    Center for Biophysics and Computational Biology, 607 South Mathews Avenue, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
4-hydroxy-3-methylbut-2-enyl diphosphate reductase
A, B
327Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: ispH (lytB, yaaE)
EC: 1.17.7.4
Find proteins for P62623 (Escherichia coli (strain K12))
Go to UniProtKB:  P62623
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SF4
Query on SF4

Download SDF File 
Download CCD File 
A, B
IRON/SULFUR CLUSTER
Fe4 S4
LJBDFODJNLIPKO-VKOJMFJBAC
 Ligand Interaction
0O3
Query on 0O3

Download SDF File 
Download CCD File 
A, B
3-(hydroxymethyl)but-3-en-1-yl trihydrogen diphosphate
C5 H12 O8 P2
DFMXRQRICFHJAS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.189 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 70.580α = 90.00
b = 80.820β = 90.00
c = 113.050γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
RemDAqdata collection
XSCALEdata scaling
XDSdata reduction
REFMACphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-02-06
    Type: Initial release
  • Version 1.1: 2017-11-15
    Type: Refinement description