title: Using Grote-Hynes theory to quantify dynamical effects on the reaction rate of enzymatic processes. The case of methyltransferases.
abstract: Dynamical effects have recently received much attention in the context of the theoretical investigation of enzymatic catalysis. In this paper we use a combination of Grote-Hynes theory with quantum mechanical/molecular mechanical modeling that is a powerful tool to understand and quantify these dynamical effects in a particular enzyme, the glycine N-methyltransferase (GNMT). Comparison of the results obtained for this enzyme with another methyltransferase (catechol O-methyltransferase, COMT) allows us to understand the different nature of the coupling of the environment to the reaction coordinate as a function of the electrostatic interaction established by the reactive subsystem. The transmission coefficients obtained using Grote-Hynes theory are in excellent agreement with molecular dynamics estimations and show that the coupling is higher in GNMT than in COMT. The larger friction observed in GNMT is explained on the basis of the interaction established by the substrate in the active site. The larger value of the friction leads to a smaller value of the reaction frequency and thus also to a larger disagreement with the estimation of the transmission coefficient based on the frozen environment approach.
authors: Departamento de Química Física y Analítica, Universidad Jaume I, 12071 Castellón, Spain.
authors: Raquel
authors: R
authors: Castillo
authors: Maite
authors: M
authors: Roca
authors: Alejandro
authors: A
authors: Soriano
authors: Vicente
authors: V
authors: Moliner
authors: Iñaki
authors: I
authors: Tuñón
mesh_terms: D008780:Methyltransferases / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D017434:Protein Structure, Tertiary
chemical_list: D008780:Methyltransferases