89771-75-5Relevant academic research and scientific papers
A T42M substitution in bacterial 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) generates enzymes with increased resistance to glyphosate.
He, Ming,Nie, Yan-Fang,Xu, Peilin
, p. 1405 - 1409 (2007/10/03)
Mutants of class I enolpyruvylshikimate 3-phosphate synthase (EPSPS) with resistance to glyphosate were produced in a previous study using the staggered extension process with aroA genes from S. typhimurium and E. coli. Two of these mutants shared a common amino acid substitution, T42M, near the hinge region between the large globular domains of EPSPS. Using site-directed mutagenisis, we produced the T42M mutants without the other amino acid changes of the original mutants. The T42M substitution alone produced enzymes with a 9- to 25-fold decreased K(m)[PEP] and a 21- to 26-fold increased K(i)[glyphosate] compared to the wild-type enzymes. These results provide more testimony for the powerful approach for protein engineering by the combination of directed evolution and rational design.
Nonenzymatic breakdown of the tetrahedral (α-carboxyketal phosphate) intermediates of MurA and AroA, two carboxyvinyl transferases. Protonation of different functional groups controls the rate and fate of breakdown
Byczynski, Bartosz,Mizyed, Shehadeh,Berti, Paul J.
, p. 12541 - 12550 (2007/10/03)
The mechanisms of nonenzymatic breakdown of the tetrahedral intermediates (THIs) of the carboxyvinyl transferases MurA and AroA were examined in order to illuminate the interplay between the inherent reactivities of the THIs and the enzymatic strategies used to promote catalysis. THI degradation was through phosphate departure, with C-O bond cleavage. It was acid catalyzed and dependent on the protonation state of the carboxyl of the α-carboxyketal phosphate functionality, with ionizations at pKa = 3.2 ± 0.1 and 4.3 ± 0.1 for MurA and AroA THIs, respectively. The solvent deuterium kinetic isotope effect for MurA THI at pL 2.0 was 1.3 ± 0.4, consistent with general acid catalysis. The pKa's suggested intramolecular general acid catalysis through protonation of the bridging oxygen of the phosphate, though H3O+ catalysis was also possible. The product distribution varied with pH. The dominant breakdown products were {pyruvate + phosphate + R-OH} (R-OH = UDP-GlcNAc or shikimate 3-phosphate) at all pH's, particularly low pH. At higher pH's, increasing proportions of ketal, arising from intramolecular substitution of phosphate by the adjacent hydroxyl and the enolpyruvyl products of phosphate elimination were observed. With MurA THI, the product distribution fitted to pK a's 1.6 and 6.2, corresponding to the expected pKa's of a phosphate monoester. C-O bond cleavage was demonstrated by the lack of monomethyl [33P]phosphate formed upon degrading MurA [ 33P]THI in 50% methanol. General acid catalysis through the bridging oxygen is consistent with the location of the previously proposed general acid catalyst for THI breakdown in AroA, Lys22.
Synthesis and evaluation of two new inhibitors of EPSP synthase
Pansegrau, Paul D.,Anderson, Karen S.,Widlanski, Theodore,Ream, Joel E.,Douglas Sammons,Sikorski, James A.,Knowles, Jeremy R.
, p. 2589 - 2592 (2007/10/02)
The enzyme EPSP synthase, EPSPS, (EC 2.5.1.19) catalyzes an unusual transfer reaction of the enolpyruvoyl moiety from phosphoenol pyruvate (2, PEP) regiospecifically to the 5-OH of shikimate 3-phosphate (1, S3P) to form 5-enol-pyruvoylshikimate 3-phosphate (3, EPSP). Two new inhibitors, (4, and 5) were prepared to probe the S3P binding site.
SHIKIMATE-DERIVED METABOLITES. 14. CHIRAL SYNTHESIS OF 5-ENOLPYRUVYL-SHIKIMATE-3-PHOSPHATE
Teng, Chia-Yu P.,Yukimoto, Yusuke,Ganem, Bruce
, p. 21 - 24 (2007/10/02)
The title compound, a key biosynthetic intermediate in the shikimate metabolic pathway, has been synthesized in good yield from (-)-shikimic acid (1)
