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Liu T, Niu Y, Cheng K, Fei Q, Liu D. Exploring the formation pathway and antioxidant properties of the sugar-smoking pigment 5-GGMF. Food Chem 2024; 442:138406. [PMID: 38219571 DOI: 10.1016/j.foodchem.2024.138406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/21/2023] [Accepted: 01/07/2024] [Indexed: 01/16/2024]
Abstract
The present study aimed to elucidate the pathway of pigment formation and identify the source of antioxidant activity during sugar smoking. Building upon previous research, this investigation replicated the sucrose cleavage process involved in sugar-smoking through model reactions to obtain distinct model reaction products. The products were analyzed using various techniques such as ultraviolet-visible spectrometry, Fourier-transform infrared spectroscopy, high-performance liquid chromatography, and high-performance liquid chromatography-tandem mass spectrometry. The findings revealed that the pyrolysis of sucrose at 330 °C yielded glucose and fructose, with fructose pyrolysis producing significantly more 5-HMF than glucose. Moreover, the antioxidant capacity of 5-HMF was found to make a substantial contribution. The primary source of 5-HMF was identified as fructose resulting from the cleavage of sucrose at 330 °C, while the primary pathway for the formation of the sugar-smoking pigment 5-GGMF was attributed to the intermolecular dehydration of 5-HMF and glucose at 150 °C.
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Affiliation(s)
- Teng Liu
- College of Food Science and Technology, Bohai University, Jinzhou 121013, China
| | - Yumin Niu
- College of Food Science and Technology, Bohai University, Jinzhou 121013, China
| | - Kexin Cheng
- College of Food Science and Technology, Bohai University, Jinzhou 121013, China
| | - Qichao Fei
- College of Food Science and Technology, Bohai University, Jinzhou 121013, China
| | - Dengyong Liu
- College of Food Science and Technology, Bohai University, Jinzhou 121013, China.
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Xiao Y, Yan Y, Do H, Rankin R, Zhao H, Qian P, Song K, Wu T, Pang CH. Understanding cellulose pyrolysis via ab initio deep learning potential field. Bioresour Technol 2024; 399:130590. [PMID: 38490462 DOI: 10.1016/j.biortech.2024.130590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/17/2024]
Abstract
Comprehensive and dynamic studies of cellulose pyrolysis reaction mechanisms are crucial in designing experiments and processes with enhanced safety, efficiency, and sustainability. The details of the pyrolysis mechanism are not readily available from experiments but can be better described via molecular dynamics (MD) simulations. However, the large size of cellulose molecules challenges accurate ab initio MD simulations, while existing reactive force field parameters lack precision. In this work, precise ab initio deep learning potentials field (DPLF) are developed and applied in MD simulations to facilitate the study of cellulose pyrolysis mechanisms. The formation mechanism and production rate of both valuable and greenhouse products from cellulose at temperatures larger than 1073 K are comprehensively described. This study underscores the critical role of advanced simulation techniques, particularly DLPF, in achieving efficient and accurate understanding of cellulose pyrolysis mechanisms, thus promoting wider industrial applications.
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Affiliation(s)
- Yuqin Xiao
- Department of Chemical and Environmental Engineering, University of Nottingham, 199 Taikang East Road, Ningbo 315100, China; Center for Intelligent and Biomimetic Systems, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518055, China
| | - Yuxin Yan
- College of Energy Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Hainam Do
- Department of Chemical and Environmental Engineering, University of Nottingham, 199 Taikang East Road, Ningbo 315100, China; Key Laboratory for Carbonaceous Wastes Processing and Process Intensification Research of Zhejiang Province, University of Nottingham, Ningbo China, Ningbo 315100, China
| | - Richard Rankin
- School of Mathematical Sciences, University of Nottingham, 199 Taikang East Road, Ningbo 315100, China
| | - Haitao Zhao
- Center for Intelligent and Biomimetic Systems, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518055, China
| | - Ping Qian
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Keke Song
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Tao Wu
- Department of Chemical and Environmental Engineering, University of Nottingham, 199 Taikang East Road, Ningbo 315100, China; Key Laboratory for Carbonaceous Wastes Processing and Process Intensification Research of Zhejiang Province, University of Nottingham, Ningbo China, Ningbo 315100, China
| | - Cheng Heng Pang
- Department of Chemical and Environmental Engineering, University of Nottingham, 199 Taikang East Road, Ningbo 315100, China; Key Laboratory for Carbonaceous Wastes Processing and Process Intensification Research of Zhejiang Province, University of Nottingham, Ningbo China, Ningbo 315100, China; Municipal Key Laboratory of Clean Energy Conversion Technologies, University of Nottingham Ningbo China, Ningbo 315100, China.
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Su B, Luo Z, Wang T, Xie C, Cheng F. Chemical kinetic behaviors at the chain initiation stage of CH 4/H 2/air mixture. J Hazard Mater 2021; 403:123680. [PMID: 33264879 DOI: 10.1016/j.jhazmat.2020.123680] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 06/12/2023]
Abstract
To intensively investigate chemical kinetic behaviors at the initial stage of CH4/H2/air mixture thoroughly, the density functional theory (CAMB3LYP/6-31 G) and a detailed mechanism (GRI-Mech3.0) were used to obtain kinetic and thermodynamic parameters. The reaction paths during the explosion process were analyzed, and the reaction rates of elementary reactions were compared with different ratios of CH4/H2/air mixture. The key reactions at the initiation stage of CH4/H2/air mixture explosion were determined, and their configurations were optimized. The reaction mechanism, reaction channel and configuration parameters of key reactions were obtained, which was verified by the intrinsic reaction coordinate (IRC) theory. Results show that H2 addition increases the laminar burning velocity, while it shortens the ignition delay time of H2/CH4/air mixture. The addition of hydrogen greatly accelerated the explosion reaction from sample 1 to sample 4. Moreover, CH4 still plays a key role at the chain initiation stage in H2/CH4/air mixture system; the addition of H2 would not compete with CH4 for triggering the explosion reaction, nor will it suppress the explosion of CH4. H2 could not replace or take precedence over the chain branching reactant (CH2O) of CH4 explosion to react with O2. Besides, H2 takes precedence over CH4 in the process of chain transfer after the chain reaction beginning, although CH4 has a distinct advantage in the chain initiation stage. The present results can provide theoretical guidance for the prevention and control of gas explosion, which may effectively reduce the explosion hazards.
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Affiliation(s)
- Bin Su
- School of Safety Science & Engineering, Xi'an University of Science and Technology, 58, Yanta Mid. Rd., Xi'an, 710054, Shaanxi, PR China
| | - Zhenmin Luo
- School of Safety Science & Engineering, Xi'an University of Science and Technology, 58, Yanta Mid. Rd., Xi'an, 710054, Shaanxi, PR China; Shaanxi Key Laboratory of Prevention and Control of Coal Fire, 58, Yanta Mid. Rd, Xi'an, 710054, Shaanxi, PR China; Shaanxi Engineering Research Center for Industrial Process Safety & Emergency Rescue, 58, Yanta Mid. Rd., Xi'an, 710054, Shaanxi, PR China.
| | - Tao Wang
- Postdoctoral Program, Xi'an University of Science and Technology, 58, Yanta Mid. Rd., Xi'an, 710054, Shaanxi, PR China.
| | - Chao Xie
- School of Safety Science & Engineering, Xi'an University of Science and Technology, 58, Yanta Mid. Rd., Xi'an, 710054, Shaanxi, PR China
| | - Fangming Cheng
- School of Safety Science & Engineering, Xi'an University of Science and Technology, 58, Yanta Mid. Rd., Xi'an, 710054, Shaanxi, PR China; Shaanxi Key Laboratory of Prevention and Control of Coal Fire, 58, Yanta Mid. Rd, Xi'an, 710054, Shaanxi, PR China; Shaanxi Engineering Research Center for Industrial Process Safety & Emergency Rescue, 58, Yanta Mid. Rd., Xi'an, 710054, Shaanxi, PR China
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Narayan B, Fathizadeh A, Templeton C, He P, Arasteh S, Elber R, Buchete NV, Levy RM. The transition between active and inactive conformations of Abl kinase studied by rock climbing and Milestoning. Biochim Biophys Acta Gen Subj 2020; 1864:129508. [PMID: 31884066 PMCID: PMC7012767 DOI: 10.1016/j.bbagen.2019.129508] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 12/11/2019] [Accepted: 12/19/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND Kinases are a family of enzymes that catalyze the transfer of the ɤ-phosphate group from ATP to a protein's residue. Malfunctioning kinases are involved in many health problems such as cardiovascular diseases, diabetes, and cancer. Kinases transitions between multiple conformations of inactive to active forms attracted considerable interest. METHOD A reaction coordinate is computed for the transition between the active to inactive conformation in Abl kinase with a focus on the DFG-in to DFG-out flip. The method of Rock Climbing is used to construct a path locally, which is subsequently optimized using a functional of the entire path. The discrete coordinate sets along the reaction path are used in a Milestoning calculation of the free energy landscape and the rate of the transition. RESULTS The estimated transition times are between a few milliseconds and seconds, consistent with simulations of the kinetics and with indirect experimental data. The activation requires the transient dissociation of the salt bridge between Lys271 and Glu286. The salt bridge reforms once the DFG motif is stabilized by a locked conformation of Phe382. About ten residues are identified that contribute significantly to the process and are included as part of the reaction space. CONCLUSIONS The transition from DFG-in to DFG-out in Abl kinase was simulated using atomic resolution of a fully solvated protein yielding detailed description of the kinetics and the mechanism of the DFG flip. The results are consistent with other computational methods that simulate the kinetics and with some indirect experimental measurements. GENERAL SIGNIFICANCE The activation of kinases includes a conformational transition of the DFG motif that is important for enzyme activity but is not accessible to conventional Molecular Dynamics. We propose a detailed mechanism for the transition, at a timescale longer than conventional MD, using a combination of reaction path and Milestoning algorithms. The mechanism includes local structural adjustments near the binding site as well as collective interactions with more remote residues.
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Affiliation(s)
- Brajesh Narayan
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
| | - Arman Fathizadeh
- Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, 201 E. 24(th) Street, 1 University Station (C0200), Austin, TX 78712-1229, USA
| | - Clark Templeton
- McKetta Department of Chemical Engineering, University of Texas at Austin, 200 E. Dean Keaton St. Stop C0400, Austin, TX 78712-1589, USA
| | - Peng He
- Department of Chemistry, Temple University, 1801 N Broad Street, Philadelphia, PA 19122, USA
| | - Shima Arasteh
- Department of Chemistry, Temple University, 1801 N Broad Street, Philadelphia, PA 19122, USA
| | - Ron Elber
- Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, 201 E. 24(th) Street, 1 University Station (C0200), Austin, TX 78712-1229, USA; Department of Chemistry, University of Texas at Austin, 2506 Speedway STOP A5300, Austin, TX 78712-1224, USA.
| | | | - Ron M Levy
- Department of Chemistry, Temple University, 1801 N Broad Street, Philadelphia, PA 19122, USA
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Aranda C, Richaud A, Méndez F, Domínguez A. Theoretical rate constant of methane oxidation from the conventional transition-state theory. J Mol Model 2018; 24:294. [PMID: 30255207 DOI: 10.1007/s00894-018-3829-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/12/2018] [Indexed: 10/28/2022]
Abstract
The potential energy surface for the first step of the methane oxidation CH4 + O2➔CH3 + HO2 was studied using the London-Eyring-Polanyi-Sato equation (LEPS) and the conventional transition-state theory (CTST). The calculated activation energy and rate constant values were in good agreement with the experimental and theoretical values reported in the literature using the shock tube technique and coupled cluster method respectively. The rate equation from CTST, although simple, provides good results to study the H-shift between methane and the oxygen molecules.
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Skeel RD, Zhao R, Post CB. A minimization principle for transition paths of maximum flux for collective variables. Theor Chem Acc 2017; 136. [PMID: 29225509 DOI: 10.1007/s00214-016-2041-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Considered is the construction of transition paths of conformational changes for proteins and other macromolecules, using methods that do not require the generation of dynamics trajectories. Special attention is given to the use of a reduced set of collective variables for describing such paths. A favored way to define transition paths is to seek channels through the transition state having cross sections with a high reactive flux (density of last hitting points of reactive trajectories). Given here is a formula for reactive flux that is independent of the parameterization of "collective variable space." This formula is needed for the principal curve of the reactive flux (as in the revised finite temperature string method) and for the maximum flux transition (MaxFlux) path. Additionally, a resistance functional is derived for narrow tubes, which when minimized yields a MaxFlux path. A strategy for minimization is outlined in the spirit of the string method. Finally, alternative approaches based on determining trajectories of high probability are considered, and it is observed that they yield paths that depend on the parameterization of collective variable space, except in the case of zero temperature, where such a path coincides with a MaxFlux path.
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Affiliation(s)
- Robert D Skeel
- Department of Computer Science, Purdue University, West Lafayette, IN, 47906 USA
| | - Ruijun Zhao
- Department of Mathematics and Statistics, Minnesota State University, Mankato, MN, 56001 USA
| | - Carol Beth Post
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, 47906 USA
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Abstract
Understanding enzyme mechanisms is a major task to achieve in order to comprehend how living cells work. Recent advances in biomolecular research provide huge amount of data on enzyme kinetics and structure. The analysis of diverse experimental results and their combination into an overall picture is, however, often challenging. Microscopic details of the enzymatic processes are often anticipated based on several hints from macroscopic experimental data. Computational biochemistry aims at creation of a computational model of an enzyme in order to explain microscopic details of the catalytic process and reproduce or predict macroscopic experimental findings. Results of such computations are in part complementary to experimental data and provide an explanation of a biochemical process at the microscopic level. In order to evaluate the mechanism of an enzyme, a structural model is constructed which can be analyzed by several theoretical approaches. Several simulation methods can and should be combined to get a reliable picture of the process of interest. Furthermore, abstract models of biological systems can be constructed combining computational and experimental data. In this review, we discuss structural computational models of enzymatic systems. We first discuss various models to simulate enzyme catalysis. Furthermore, we review various approaches how to characterize the enzyme mechanism both qualitatively and quantitatively using different modeling approaches.
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Affiliation(s)
- Martin Culka
- Computational Biochemistry, University of Bayreuth, Bayreuth, Germany
| | - Florian J Gisdon
- Computational Biochemistry, University of Bayreuth, Bayreuth, Germany
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Zhou Y, Ojeda-May P, Nagaraju M, Pu J. Toward Determining ATPase Mechanism in ABC Transporters: Development of the Reaction Path-Force Matching QM/MM Method. Methods Enzymol 2016; 577:185-212. [PMID: 27498639 PMCID: PMC4985252 DOI: 10.1016/bs.mie.2016.05.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are ubiquitous ATP-dependent membrane proteins involved in translocations of a wide variety of substrates across cellular membranes. To understand the chemomechanical coupling mechanism as well as functional asymmetry in these systems, a quantitative description of how ABC transporters hydrolyze ATP is needed. Complementary to experimental approaches, computer simulations based on combined quantum mechanical and molecular mechanical (QM/MM) potentials have provided new insights into the catalytic mechanism in ABC transporters. Quantitatively reliable determination of the free energy requirement for enzymatic ATP hydrolysis, however, requires substantial statistical sampling on QM/MM potential. A case study shows that brute force sampling of ab initio QM/MM (AI/MM) potential energy surfaces is computationally impractical for enzyme simulations of ABC transporters. On the other hand, existing semiempirical QM/MM (SE/MM) methods, although affordable for free energy sampling, are unreliable for studying ATP hydrolysis. To close this gap, a multiscale QM/MM approach named reaction path-force matching (RP-FM) has been developed. In RP-FM, specific reaction parameters for a selected SE method are optimized against AI reference data along reaction paths by employing the force matching technique. The feasibility of the method is demonstrated for a proton transfer reaction in the gas phase and in solution. The RP-FM method may offer a general tool for simulating complex enzyme systems such as ABC transporters.
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Affiliation(s)
- Y Zhou
- Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - P Ojeda-May
- Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - M Nagaraju
- Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - J Pu
- Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States.
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Kearns FL, Hudson PS, Boresch S, Woodcock HL. Methods for Efficiently and Accurately Computing Quantum Mechanical Free Energies for Enzyme Catalysis. Methods Enzymol 2016; 577:75-104. [PMID: 27498635 DOI: 10.1016/bs.mie.2016.05.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Enzyme activity is inherently linked to free energies of transition states, ligand binding, protonation/deprotonation, etc.; these free energies, and thus enzyme function, can be affected by residue mutations, allosterically induced conformational changes, and much more. Therefore, being able to predict free energies associated with enzymatic processes is critical to understanding and predicting their function. Free energy simulation (FES) has historically been a computational challenge as it requires both the accurate description of inter- and intramolecular interactions and adequate sampling of all relevant conformational degrees of freedom. The hybrid quantum mechanical molecular mechanical (QM/MM) framework is the current tool of choice when accurate computations of macromolecular systems are essential. Unfortunately, robust and efficient approaches that employ the high levels of computational theory needed to accurately describe many reactive processes (ie, ab initio, DFT), while also including explicit solvation effects and accounting for extensive conformational sampling are essentially nonexistent. In this chapter, we will give a brief overview of two recently developed methods that mitigate several major challenges associated with QM/MM FES: the QM non-Boltzmann Bennett's acceptance ratio method and the QM nonequilibrium work method. We will also describe usage of these methods to calculate free energies associated with (1) relative properties and (2) along reaction paths, using simple test cases with relevance to enzymes examples.
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Affiliation(s)
- F L Kearns
- University of South Florida, Tampa, FL, United States
| | - P S Hudson
- University of South Florida, Tampa, FL, United States
| | - S Boresch
- Faculty of Chemistry, University of Vienna, Vienna, Austria.
| | - H L Woodcock
- University of South Florida, Tampa, FL, United States.
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Hudson PS, White JK, Kearns FL, Hodoscek M, Boresch S, Lee Woodcock H. Efficiently computing pathway free energies: New approaches based on chain-of-replica and Non-Boltzmann Bennett reweighting schemes. Biochim Biophys Acta Gen Subj 2014; 1850:944-953. [PMID: 25239198 DOI: 10.1016/j.bbagen.2014.09.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND Accurately modeling condensed phase processes is one of computation's most difficult challenges. Include the possibility that conformational dynamics may be coupled to chemical reactions, where multiscale (i.e., QM/MM) methods are needed, and this task becomes even more daunting. METHODS Free energy simulations (i.e., molecular dynamics), multiscale modeling, and reweighting schemes. RESULTS Herein, we present two new approaches for mitigating the aforementioned challenges. The first is a new chain-of-replica method (off-path simulations, OPS) for computing potentials of mean force (PMFs) along an easily defined reaction coordinate. This development is coupled with a new distributed, highly-parallel replica framework (REPDstr) within the CHARMM package. Validation of these new schemes is carried out on two processes that undergo conformational changes. First is the simple torsional rotation of butane, while a much more challenging glycosidic rotation (in vacuo and solvated) is the second. Additionally, a new approach that greatly improves (i.e., possibly an order of magnitude) the efficiency of computing QM/MM PMFs is introduced and compared to standard schemes. Our efforts are grounded in the recently developed method for efficiently computing QM-based free energies (i.e., QM-Non-Boltzmann Bennett, QM-NBB). Again, we validate this new technique by computing the QM/MM PMF of butane's torsional rotation. CONCLUSIONS The OPS-REPDstr method is a promising new approach that overcomes many limitations of standard pathway simulations in CHARMM. The combination of QM-NBB with pathway techniques is very promising as it offers significant advantages over current procedures. GENERAL SIGNIFICANCE Efficiently computing potentials of mean force is a major, unresolved, area of interest. This article is part of a Special Issue entitled Recent developments of molecular dynamics.
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Affiliation(s)
- Phillip S Hudson
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, FL 33620-5250, USA
| | - Justin K White
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, FL 33620-5250, USA
| | - Fiona L Kearns
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, FL 33620-5250, USA
| | - Milan Hodoscek
- Center for Molecular Modeling, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
| | - Stefan Boresch
- Department of Computational Biological Chemistry, Faculty of Chemistry, University of Vienna, Währingerstraße 17, A-1090 Vienna, Austria
| | - H Lee Woodcock
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, FL 33620-5250, USA.
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