PDBsum entry 1e5x

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Threonine biosynthesis PDB id
Protein chains
451 a.a. *
Waters ×388
* Residue conservation analysis
PDB id:
Name: Threonine biosynthesis
Title: Structure of threonine synthase from arabidopsis thaliana
Structure: Threonine synthase. Chain: a, b. Engineered: yes
Source: Arabidopsis thaliana. Mouse-ear cress. Organism_taxid: 3702. Organelle: chloroplast. Cellular_location: chloroplast. Plasmid: pet23. Gene: nuclear. Expressed in: escherichia coli. Expression_system_taxid: 511693.
Biol. unit: Homo-Dimer (from PDB file)
2.25Å     R-factor:   0.222     R-free:   0.243
Authors: K.Thomazeau,G.Curien,R.Dumas,V.Biou
Key ref: K.Thomazeau et al. (2001). Crystal structure of threonine synthase from Arabidopsis thaliana. Protein Sci, 10, 638-648. PubMed id: 11344332
04-Aug-00     Release date:   02-Aug-01    
Go to PROCHECK summary

Protein chains
Pfam   ArchSchema ?
Q9S7B5  (THRC1_ARATH) -  Threonine synthase 1, chloroplastic
526 a.a.
451 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 1 residue position (black cross)

 Enzyme reactions 
   Enzyme class: E.C.  - Threonine synthase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]

Threonine Biosynthesis
      Reaction: O-phospho-L-homoserine + H2O = L-threonine + phosphate
+ H(2)O
= L-threonine
+ phosphate
      Cofactor: Pyridoxal 5'-phosphate
Pyridoxal 5'-phosphate
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     plastid   4 terms 
  Biological process     metabolic process   4 terms 
  Biochemical function     catalytic activity     4 terms  


Protein Sci 10:638-648 (2001)
PubMed id: 11344332  
Crystal structure of threonine synthase from Arabidopsis thaliana.
K.Thomazeau, G.Curien, R.Dumas, V.Biou.
Threonine synthase (TS) is a PLP-dependent enzyme that catalyzes the last reaction in the synthesis of threonine from aspartate. In plants, the methionine pathway shares the same substrate, O-phospho-L-homoserine (OPH), and TS is activated by S-adenosyl-methionine (SAM), a downstream product of methionine synthesis. This positive allosteric effect triggered by the product of another pathway is specific to plants. The crystal structure of Arabidopsis thaliana apo threonine synthase was solved at 2.25 A resolution from triclinic crystals using MAD data from the selenomethionated protein. The structure reveals a four-domain dimer with a two-stranded beta-sheet arm protruding from one monomer onto the other. This domain swap could form a lever through which the allosteric effect is transmitted. The N-terminal domain (domain 1) has a unique fold and is partially disordered, whereas the structural core (domains 2 and 3) shares the functional domain of PLP enzymes of the same family. It also has similarities with SAM-dependent methyltransferases. Structure comparisons allowed us to propose potential sites for pyridoxal-phosphate and SAM binding on TS; they are close to regions that are disordered in the absence of these molecules.

Literature references that cite this PDB file's key reference

  PubMed id Reference
  20019093 G.Jander, and V.Joshi (2010).
Recent progress in deciphering the biosynthesis of aspartate-derived amino acids in plants.
  Mol Plant, 3, 54-65.  
20186554 V.Joshi, J.G.Joung, Z.Fei, and G.Jander (2010).
Interdependence of threonine, methionine and isoleucine metabolism in plants: accumulation and transcriptional regulation under abiotic stress.
  Amino Acids, 39, 933-947.  
19019829 Q.Sun, R.Collins, S.Huang, L.Holmberg-Schiavone, G.S.Anand, C.H.Tan, S.van-den-Berg, L.W.Deng, P.K.Moore, T.Karlberg, and J.Sivaraman (2009).
Structural Basis for the Inhibition Mechanism of Human Cystathionine {gamma}-Lyase, an Enzyme Responsible for the Production of H2S.
  J Biol Chem, 284, 3076-3085.
PDB codes: 2nmp 3cog 3elp
16525757 R.A.Azevedo, M.Lancien, and P.J.Lea (2006).
The aspartic acid metabolic pathway, an exciting and essential pathway in plants.
  Amino Acids, 30, 143-162.  
15890029 K.H.Jhee, and W.D.Kruger (2005).
The role of cystathionine beta-synthase in homocysteine metabolism.
  Antioxid Redox Signal, 7, 813-822.  
11526338 K.Thomazeau, G.Curien, A.Thompson, R.Dumas, and V.Biou (2001).
MAD on threonine synthase: the phasing power of oxidized selenomethionine.
  Acta Crystallogr D Biol Crystallogr, 57, 1337-1340.  
The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB codes are shown on the right.