Disease relevance of MTO2

• To further characterize this unusual role for S-adenosylmethionine, the Arabidopsis thaliana threonine synthase was overexpressed in Escherichia coli, purified to homogeneity, and then used for kinetic and enzyme-bound pyridoxal 5'-phosphate fluorescence equilibrium-binding experiments [1].
• To investigate the regulation of this branch point, we engineered TS antisense potato (Solanum tuberosum cv Désirée) plants using the constitutive cauliflower mosaic virus 35S promoter [2].

High impact information on MTO2

• Unlike the enzyme from microorganisms, plant TS is activated by S-adenosylmethionine (AdoMet) [3].
• Threonine synthase (TS) is a fold-type II pyridoxal phosphate (PLP)-dependent enzyme that catalyzes the ultimate step of threonine synthesis in plants and microorganisms [3].
• Allosteric threonine synthase. Reorganization of the pyridoxal phosphate site upon asymmetric activation through S-adenosylmethionine binding to a novel site [3].
• Antisense inhibition of threonine synthase leads to high methionine content in transgenic potato plants [2].
• 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 [4].

Associations of MTO2 with chemical compounds

• MAD on threonine synthase: the phasing power of oxidized selenomethionine [5].
• Plants expressing the sense orientation of TS showed a higher level of threonine, increased expression level of CGS, and a significantly higher level of S-methylmethionine, the transport form of methionine [6].

Other interactions of MTO2

• From the data presented here and in previous work we conclude that threonine synthase and not cystathionine gamma-synthase as expected from studies of Arabidopsis constitutes the main regulatory control point of methionine synthesis in potato [7].

References