The difference-based adaptive solvation quantum mechanics/molecular mechanics (adQM/MM) method (J. Chem. Theory Comput.2009, 5, 2212) as implemented in the Amber software was applied to the study of several chemical processes in solution. The adQM/MM method is based on an efficient selection scheme that enables quantum-mechanical treatment of the active region of a molecular system in solution taking explicitly into account diffusion of solvent molecules between the QM and the MM regions. Specifically, adQM/MM molecular dynamics simulations are carried out to characterize (1) the free energy profiles of halide exchange SN2 reactions in water, (2) the hydration structure of the Cl(-) ion, and (3) the solvation structure of the zwitterionic form of glycine in water. A comparison is made with the results obtained using standard MM and QM/MM methods as well as with the available fully QM and experimental data. In all cases, it is shown that the adaptive QM/MM simulations provide a physically realistic description of the system of interest.
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Methods Enzymol
November 2024
Departamento de Físico-Química, Facultad de Ciencias Químicas, Universidad de Concepción, Concepción, Chile. Electronic address:
The rising levels of atmospheric CO and its impact on climate change call for new methods to transform this greenhouse gas into beneficial compounds. Carboxylases have a significant role in the carbon cycle, converting gigatons of CO into biomass annually. One of the most effective and fastest carboxylases is crotonyl-CoA carboxylase/reductase (Ccr).
View Article and Find Full Text PDFJ Phys Chem A
October 2024
Department of Chemistry, University of Graz, Heinrichstraße 28/IV, 8010 Graz, Austria.
Chem Asian J
October 2024
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
The importance of anions in various processes has led to a search for molecules that can effectively recognize and interact with these anions. This study explores how the tetraglycine [(Gly)] peptide in its zwitterionic, neutral, and terminally capped forms acts as a receptor for HPO and HSO anions within the framework of supramolecular host-guest chemistry. Using molecular dynamics (MD) simulations, we obtained the conformations of the receptor-anion complexes.
View Article and Find Full Text PDFACS Catal
July 2024
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
The task of adapting enzymes for specific applications is often hampered by our incomplete ability to tune and tailor catalytic functions, particularly when seeking increased activity. Here, we develop and demonstrate a rational approach to address this challenge, applied to ketol-acid reductoisomerase (KARI), which has uses in industrial-scale isobutanol production. While traditional structure-based computational enzyme redesign strategies typically focus on the enzyme-bound ground state (GS) and transition state (TS), we postulated that additionally treating the underlying dynamics of complete turnover events that connect and pass through both states could further elucidate the structural properties affecting catalysis and help identify mutations that lead to increased catalytic activity.
View Article and Find Full Text PDFJ Chem Theory Comput
July 2024
Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.
Water-mediated proton transfer reactions are central for catalytic processes in a wide range of biochemical systems, ranging from biological energy conversion to chemical transformations in the metabolism. Yet, the accurate computational treatment of such complex biochemical reactions is highly challenging and requires the application of multiscale methods, in particular hybrid quantum/classical (QM/MM) approaches combined with free energy simulations. Here, we combine the unique exploration power of new advanced sampling methods with density functional theory (DFT)-based QM/MM free energy methods for multiscale simulations of long-range protonation dynamics in biological systems.
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