74708-38-6Relevant articles and documents
Increased dynamic effects in a catalytically compromised variant of escherichia coli dihydrofolate reductase
Ruiz-Pernia, J. Javier,Luk, Louis Y. P.,Garcia-Meseguer, Rafael,Marti, Sergio,Loveridge, E. Joel,Tunon, Inaki,Moliner, Vicent,Allemann, Rudolf K.
, p. 18689 - 18696 (2013)
Isotopic substitution (15N, 13C, 2H) of a catalytically compromised variant of Escherichia coli dihydrofolate reductase, EcDHFR-N23PP/S148A, has been used to investigate the effect of these mutations on catalysis. The reduction of the rate constant of the chemical step in the EcDHFR-N23PP/S148A catalyzed reaction is essentially a consequence of an increase of the quasi-classical free energy barrier and to a minor extent of an increased number of recrossing trajectories on the transition state dividing surface. Since the variant enzyme is less well set up to catalyze the reaction, a higher degree of active site reorganization is needed to reach the TS. Although millisecond active site motions are lost in the variant, there is greater flexibility on the femtosecond time scale. The dynamic knockout EcDHFR-N23PP/S148A is therefore a dynamic knock-in at the level of the chemical step, and the increased dynamic coupling to the chemical coordinate is in fact detrimental to catalysis. This finding is most likely applicable not just to hydrogen transfer in EcDHFR but also to other enzymatic systems.
Chemoenzymatic Assembly of Isotopically Labeled Folates
Angelastro, Antonio,Dawson, William M.,Luk, Louis Y. P.,Loveridge, E. Joel,Allemann, Rudolf K.
supporting information, p. 13047 - 13054 (2017/09/26)
Pterin-containing natural products have diverse functions in life, but an efficient and easy scheme for their in vitro synthesis is not available. Here we report a chemoenzymatic 14-step, one-pot synthesis that can be used to generate 13C- and 15N-labeled dihydrofolates (H2F) from glucose, guanine, and p-aminobenzoyl-l-glutamic acid. This synthesis stands out from previous approaches to produce H2F in that the average yield of each step is >91% and it requires only a single purification step. The use of a one-pot reaction allowed us to overcome potential problems with individual steps during the synthesis. The availability of labeled dihydrofolates allowed the measurement of heavy-atom isotope effects for the reaction catalyzed by the drug target dihydrofolate reductase and established that protonation at N5 of H2F and hydride transfer to C6 occur in a stepwise mechanism. This chemoenzymatic pterin synthesis can be applied to the efficient production of other folates and a range of other natural compounds with applications in nutritional, medical, and cell-biological research.
Aqueous diastereoselective hydrogenation of folic acid to tetrahydrofolic acid in the presence of water-soluble Rh and Ir diphosphine complexes
Pugin, Benoit,Groehn, Viola,Moser, Rudolf,Blaser, Hans-Ulrich
, p. 544 - 549 (2007/10/03)
Rhodium and iridium catalysts with chiral, water soluble diphosphine ligands, were used for the diastereoselective hydrogenation of folic acid disodium salt in water. Using a modified Rh/Josiphos type at 30 °C, l-tetrahydrofolic acid, a relevant pharmaceutical intermediate, was obtained with a selectivity of up to 49% de; at 70 °C turnover numbers of up to 2800 were achieved, albeit with lower selectivity. These results define the state of the art for this reaction.
