3MB2

Kinetic and Structural Characterization of a Heterohexamer 4-Oxalocrotonate Tautomerase from Chloroflexus aurantiacus J-10-fl: Implications for Functional and Structural Diversity in the Tautomerase Superfamily


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.41 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.206 

wwPDB Validation   3D Report Full Report


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Literature

Kinetic and structural characterization of a heterohexamer 4-oxalocrotonate tautomerase from Chloroflexus aurantiacus J-10-fl: implications for functional and structural diversity in the tautomerase superfamily

Burks, E.A.Fleming, C.D.Mesecar, A.D.Whitman, C.P.Pegan, S.D.

(2010) Biochemistry 49: 5016-5027

  • DOI: 10.1021/bi100502z
  • Primary Citation of Related Structures:  
    3MB2

  • PubMed Abstract: 
  • 4-Oxalocrotonate tautomerase (4-OT) isozymes play prominent roles in the bacterial utilization of aromatic hydrocarbons as sole carbon sources. These enzymes catalyze the conversion of 2-hydroxy-2,4-hexadienedioate (or 2-hydroxymuconate) to 2-oxo-3-hexenedioate, where Pro-1 functions as a general base and shuttles a proton from the 2-hydroxyl group of the substrate to the C-5 position of the product ...

    4-Oxalocrotonate tautomerase (4-OT) isozymes play prominent roles in the bacterial utilization of aromatic hydrocarbons as sole carbon sources. These enzymes catalyze the conversion of 2-hydroxy-2,4-hexadienedioate (or 2-hydroxymuconate) to 2-oxo-3-hexenedioate, where Pro-1 functions as a general base and shuttles a proton from the 2-hydroxyl group of the substrate to the C-5 position of the product. 4-OT, a homohexamer from Pseudomonas putida mt-2, is the most extensively studied 4-OT isozyme and the founding member of the tautomerase superfamily. A search of five thermophilic bacterial genomes identified a coded amino acid sequence in each that had been annotated as a tautomerase-like protein but lacked Pro-1. However, a nearby sequence has Pro-1, but the sequence is not annotated as a tautomerase-like protein. To characterize this group of proteins, two genes from Chloroflexus aurantiacus J-10-fl were cloned, and the corresponding proteins were expressed. Kinetic, biochemical, and X-ray structural analyses show that the two expressed proteins form a functional heterohexamer 4-OT (hh4-OT), composed of three alphabeta dimers. Like the P. putida enzyme, hh4-OT requires the amino-terminal proline and two arginines for the conversion of 2-hydroxymuconate to the product, implicating an analogous mechanism. In contrast to 4-OT, hh4-OT does not exhibit the low-level activity of another tautomerase superfamily member, the heterohexamer trans-3-chloroacrylic acid dehalogenase (CaaD). Characterization of hh4-OT enables functional assignment of the related enzymes, highlights the diverse ways the beta-alpha-beta building block can be assembled into an active enzyme, and provides further insight into the molecular basis of the low-level CaaD activity in 4-OT.


    Organizational Affiliation

    Division of Medicinal Chemistry, College of Pharmacy, The University of Texas, Austin, Texas 78712, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
4-oxalocrotonate tautomerase family enzyme - alpha subunitA, C, E, G, I, K72Chloroflexus aurantiacus J-10-flMutation(s): 0 
Gene Names: 4-oxalocrotonate tautomeraseCaur_1354
EC: 5.3.2.2
Find proteins for A9W9U6 (Chloroflexus aurantiacus (strain ATCC 29366 / DSM 635 / J-10-fl))
Explore A9W9U6 
Go to UniProtKB:  A9W9U6
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
4-oxalocrotonate tautomerase family enzyme - beta subunitB, D, F, H, J, L72Chloroflexus aurantiacus J-10-flMutation(s): 0 
Gene Names: 4-oxalocrotonate tautomeraseCaur_1358
EC: 5.3.2.2
Find proteins for A9W9V0 (Chloroflexus aurantiacus (strain ATCC 29366 / DSM 635 / J-10-fl))
Explore A9W9V0 
Go to UniProtKB:  A9W9V0
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download Ideal Coordinates CCD File 
AA [auth K] , BA [auth L] , CA [auth L] , M [auth A] , N [auth A] , O [auth C] , P [auth C] , Q [auth C] , 
AA [auth K],  BA [auth L],  CA [auth L],  M [auth A],  N [auth A],  O [auth C],  P [auth C],  Q [auth C],  R [auth D],  S [auth E],  T [auth E],  U [auth F],  V [auth G],  W [auth H],  X [auth I],  Y [auth I],  Z [auth K]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.41 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.206 
  • Space Group: P 31
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.062α = 90
b = 106.062β = 90
c = 109.961γ = 120
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-06-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Source and taxonomy, Version format compliance