1BJP

CRYSTAL STRUCTURE OF 4-OXALOCROTONATE TAUTOMERASE INACTIVATED BY 2-OXO-3-PENTYNOATE AT 2.4 ANGSTROMS RESOLUTION


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.206 

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This is version 1.2 of the entry. See complete history


Literature

Crystal structure of 4-oxalocrotonate tautomerase inactivated by 2-oxo-3-pentynoate at 2.4 A resolution: analysis and implications for the mechanism of inactivation and catalysis.

Taylor, A.B.Czerwinski, R.M.Johnson Jr., W.H.Whitman, C.P.Hackert, M.L.

(1998) Biochemistry 37: 14692-14700

  • DOI: 10.1021/bi981607j
  • Primary Citation of Related Structures:  
    1BJP

  • PubMed Abstract: 
  • The crystal structure of 4-oxalocrotonate tautomerase (4-OT) inactivated by the active site-directed irreversible inhibitor 2-oxo-3-pentynoate (2-OP) has been determined to 2.4 A resolution. The structure of the enzyme covalently modified at Pro-1 by the resulting 2-oxo-3-pentenoate adduct is nearly superimposable on that of the free enzyme and confirms that the active site is located in a hydrophobic region surrounding Pro-1 ...

    The crystal structure of 4-oxalocrotonate tautomerase (4-OT) inactivated by the active site-directed irreversible inhibitor 2-oxo-3-pentynoate (2-OP) has been determined to 2.4 A resolution. The structure of the enzyme covalently modified at Pro-1 by the resulting 2-oxo-3-pentenoate adduct is nearly superimposable on that of the free enzyme and confirms that the active site is located in a hydrophobic region surrounding Pro-1. Both structures can be described as a trimer of dimers where each dimer consists of a four-stranded beta-sheet with two antiparallel alpha-helices on one side. Examination of the structure also reveals noncovalent interactions between the adduct and two residues in the active site. The epsilon and eta nitrogens of the guanidinium side chain of Arg-39" from a neighboring dimer interact respectively with the C-2 carbonyl oxygen and one C-1 carboxylate oxygen of the adduct while the side chain of Arg-61' from the same dimer as the modified Pro-1 interacts with the C-1 carboxylate group in a bidentate fashion. An additional interaction to the 2-oxo group of the adduct is provided by one of the two ordered water molecules within the active site region. These interactions coupled with the observation that 2-oxo-3-butynoate is a more potent irreversible inhibitor of 4-oxalocrotonate tautomerase than is 2-OP suggest that Arg-39" and the ordered water molecule polarize the carbonyl group of 2-OP which facilitates a Michael reaction between Pro-1 and the acetylene compound. On the basis of the crystal structure, a mechanism for the enzyme-catalyzed reaction is proposed.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, College of Pharmacy, The University of Texas, Austin 78712-1071, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
4-OXALOCROTONATE TAUTOMERASEA, B, C, D, E62Pseudomonas putidaMutation(s): 0 
Gene Names: xylH
EC: 5.3.2 (PDB Primary Data), 5.3.2.6 (UniProt)
UniProt
Find proteins for Q01468 (Pseudomonas putida)
Explore Q01468 
Go to UniProtKB:  Q01468
Protein Feature View
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.206 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 78.7α = 90
b = 78.7β = 90
c = 314.6γ = 120
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-12-02
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance