2ORM

Crystal Structure of the 4-Oxalocrotonate Tautomerase Homologue DmpI from Helicobacter pylori.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.217 

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This is version 1.2 of the entry. See complete history


Literature

Kinetic and structural characterization of DmpI from Helicobacter pylori and Archaeoglobus fulgidus, two 4-oxalocrotonate tautomerase family members.

Almrud, J.J.Dasgupta, R.Czerwinski, R.M.Kern, A.D.Hackert, M.L.Whitman, C.P.

(2010) Bioorg Chem 38: 252-259

  • DOI: https://doi.org/10.1016/j.bioorg.2010.07.002
  • Primary Citation of Related Structures:  
    2ORM, 3M20, 3M21

  • PubMed Abstract: 

    The tautomerase superfamily consists of structurally homologous proteins that are characterized by a β-α-β fold and a catalytic amino-terminal proline. 4-Oxalocrotonate tautomerase (4-OT) family members have been identified and categorized into five subfamilies on the basis of multiple sequence alignments and the conservation of key catalytic and structural residues. Representative members from two subfamilies have been cloned, expressed, purified, and subjected to kinetic and structural characterization. The crystal structure of DmpI from Helicobacter pylori (HpDmpI), a 4-OT homolog in subfamily 3, has been determined to high resolution (1.8Å and 2.1Å) in two different space groups. HpDmpI is a homohexamer with an active site cavity that includes Pro-1, but lacks the equivalent of Arg-11 and Arg-39 found in 4-OT. Instead, the side chain of Lys-36 replaces that of Arg-11 in a manner similar to that observed in the trimeric macrophage migration inhibitory factor (MIF), which is the title protein of another family in the superfamily. The electrostatic surface of the active site is also quite different and suggests that HpDmpI might prefer small, monoacid substrates. A kinetic analysis of the enzyme is consistent with the structural analysis, but a biological role for the enzyme remains elusive. The crystal structure of DmpI from Archaeoglobus fulgidus (AfDmpI), a 4-OT homolog in subfamily-4, has been determined to 2.4Å resolution. AfDmpI is also a homohexamer, with a proposed active site cavity that includes Pro-1, but lacks any other residues that are readily identified as catalytic ones related to 4-OT activity. Indeed, the electrostatic potential of the active site differs significantly in that it is mostly neutral, in contrast to the usual electropositive features found in other 4-OT family members, suggesting that AfDmpI might accommodate hydrophobic substrates. A kinetic analysis has been carried out, but does not provide any clues about the type of reaction the enzyme might catalyze.


  • Organizational Affiliation

    The University of Texas, Austin, 78712-1071, United States.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Probable tautomerase HP0924
A, B, C, D, E
A, B, C, D, E, F
67Helicobacter pylori J99Mutation(s): 0 
Gene Names: dmpi (GI 7449587)
EC: 5.3.2
UniProt
Find proteins for O25581 (Helicobacter pylori (strain ATCC 700392 / 26695))
Explore O25581 
Go to UniProtKB:  O25581
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO25581
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.217 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 41.83α = 90
b = 50.77β = 99.13
c = 89.31γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
AMoREphasing
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-02-12
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Derived calculations, Source and taxonomy, Version format compliance
  • Version 1.2: 2023-08-30
    Changes: Data collection, Database references, Refinement description