3AEY

Apo form of threonine synthase from Thermus thermophilus HB8


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.190 
  • R-Value Observed: 0.190 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Product-assisted catalysis as the basis of the reaction specificity of threonine synthase.

Murakawa, T.Machida, Y.Hayashi, H.

(2011) J Biol Chem 286: 2774-2784

  • DOI: 10.1074/jbc.M110.186205
  • Primary Citation of Related Structures:  
    3AEX, 3AEY

  • PubMed Abstract: 
  • Threonine synthase (TS), which is a pyridoxal 5'-phosphate (PLP)-dependent enzyme, catalyzes the elimination of the γ-phosphate group from O-phospho-L-homoserine (OPHS) and the subsequent addition of water at Cβ to form L-threonine. The catalytic course of TS is the most complex among the PLP enzymes, and it is an intriguing problem how the elementary steps are controlled in TS to carry out selective reactions ...

    Threonine synthase (TS), which is a pyridoxal 5'-phosphate (PLP)-dependent enzyme, catalyzes the elimination of the γ-phosphate group from O-phospho-L-homoserine (OPHS) and the subsequent addition of water at Cβ to form L-threonine. The catalytic course of TS is the most complex among the PLP enzymes, and it is an intriguing problem how the elementary steps are controlled in TS to carry out selective reactions. When L-vinylglycine was added to Thermus thermophilus HB8 TS in the presence of phosphate, L-threonine was formed with k(cat) and reaction specificity comparable with those when OPHS was used as the substrate. However, in the absence of phosphate or when sulfate was used in place of phosphate, only the side reaction product, α-ketobutyrate, was formed. Global analysis of the spectral changes in the reaction of TS with L-threonine showed that compared with the more acidic sulfate ion, the phosphate ion decreased the energy levels of the transition states of the addition of water at the Cβ of the PLP-α-aminocrotonate aldimine (AC) and the transaldimination to form L-threonine. The x-ray crystallographic analysis of TS complexed with an analog for AC gave a distinct electron density assigned to the phosphate ion derived from the solvent near the Cβ of the analog. These results indicated that the phosphate ion released from OPHS by γ-elimination acts as the base catalyst for the addition of water at Cβ of AC, thereby providing the basis of the reaction specificity. The phosphate ion is also considered to accelerate the protonation/deprotonation at Cγ.


    Organizational Affiliation

    Department of Biochemistry, Faculty of Medicine, Osaka Medical College, Takatsuki 569-8686, Japan.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Threonine synthaseA, B351Thermus thermophilus HB8Mutation(s): 0 
Gene Names: TTHA0491
EC: 4.2.3.1
Find proteins for Q5SL02 (Thermus thermophilus (strain HB8 / ATCC 27634 / DSM 579))
Explore Q5SL02 
Go to UniProtKB:  Q5SL02
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.190 
  • R-Value Observed: 0.190 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 112.969α = 90
b = 112.969β = 90
c = 150.262γ = 120
Software Package:
Software NamePurpose
DNAdata collection
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-11-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance