1E5X

Structure of threonine synthase from Arabidopsis thaliana

Summary for 1E5X

• Entry DOI: 10.2210/pdb1e5x/pdb
• Descriptor: THREONINE SYNTHASE (2 entities in total)
• Functional Keywords: threonine biosynthesis, plp enzyme, s-adenosyl-methionine, allostery
• Biological source: ARABIDOPSIS THALIANA (MOUSE-EAR CRESS)
• Total number of polymer chains: 2
• Total formula weight: 108116.23

Authors

Thomazeau, K.,Curien, G.,Dumas, R.,Biou, V. (deposition date: 2000-08-04, release date: 2001-08-02, Last modification date: 2025-04-09)

Primary citation

Thomazeau, K.,Curien, G.,Dumas, R.,Biou, V.
Crystal Structure of Threonine Synthase from Arabidopsis Thaliana
Protein Sci., 10:638-, 2001

PubMed Abstract: 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.

PubMed: 11344332
DOI: 10.1110/PS.44301

Experimental method

X-RAY DIFFRACTION (2.25 Å)