Derivation of Force Field Parameters, and Force Field and Quantum Mechanical Studies of Layered α- and γ-Zirconium Phosphates

1999 ◽  
Vol 38 (19) ◽  
pp. 4249-4255 ◽  
Author(s):  
Giulio Alberti ◽  
Antonio Grassi ◽  
Giuseppe M. Lombardo ◽  
Giuseppe C. Pappalardo ◽  
Riccardo Vivani
ChemInform ◽  
2010 ◽  
Vol 30 (48) ◽  
pp. no-no
Author(s):  
Giulio Alberti ◽  
Antonio Grassi ◽  
Giuseppe M. Lombardo ◽  
Giuseppe C. Pappalardo ◽  
Riccardo Vivani

2019 ◽  
Author(s):  
Alice Allen ◽  
Michael J. Robertson ◽  
Michael C. Payne ◽  
Daniel Cole

<div><div><div><p>Molecular mechanics force field parameters for macromolecules, such as proteins, are traditionally fit to reproduce experimental properties of small molecules, and thus they neglect system-specific polarization. In this paper, we introduce a complete protein force field that is designed to be compatible with the QUantum mechanical BEspoke (QUBE) force field by deriving non-bonded parameters directly from the electron density of the specific protein under study. The main backbone and sidechain protein torsional parameters are re-derived in this work by fitting to quantum mechanical dihedral scans for compatibility with QUBE non-bonded parameters. Software is provided for the preparation of QUBE input files. The accuracy of the new force field, and the derived torsional parameters, are tested by comparing the conformational preferences of a range of peptides and proteins with experimental measurements. Accurate backbone and sidechain conformations are obtained in molecular dynamics simulations of dipeptides, with NMR J coupling errors comparable to the widely-used OPLS force field. In simulations of five folded proteins, the secondary structure is generally retained and the NMR J coupling errors are similar to standard transferable force fields, although some loss of the experimental structure is observed in certain regions of the proteins. With several avenues for further development, the use of system-specific non-bonded force field parameters is a promising approach for next-generation simulations of biological molecules.</p></div></div></div>


Author(s):  
Alice Allen ◽  
Michael J. Robertson ◽  
Michael C. Payne ◽  
Daniel Cole

<div><div><div><p>Molecular mechanics force field parameters for macromolecules, such as proteins, are traditionally fit to reproduce experimental properties of small molecules, and thus they neglect system-specific polarization. In this paper, we introduce a complete QUantum mechanical BEspoke (QUBE) protein force field, which derives non-bonded parameters directly from the electron density of the specific protein under study. The main backbone and sidechain protein torsional parameters are re-derived in this work by fitting to quantum mechanical dihedral scans for compatibibility with QUBE non-bonded parameters. Software is provided for the preparation of QUBE input files. The accuracy of the new force field, and the derived torsional parameters, are tested by comparing the conformational preferences of a range of peptides and proteins with experimental measurements. Accurate backbone and sidechain conformations are obtained in molecular dynamics simulations of dipeptides, with NMR J coupling errors comparable to the widely-used OPLS force field. In simulations of five folded proteins, the secondary structure is generally retained and the NMR J coupling errors are similar to standard transferable force fields, although some loss of the experimental structure is observed in certain regions of the proteins. Overall, with several avenues for further development, the use of system-specific non-bonded force field parameters is a promising approach for next-generation simulations of biological molecules.</p></div></div></div>


2019 ◽  
Author(s):  
Alice Allen ◽  
Michael J. Robertson ◽  
Michael C. Payne ◽  
Daniel Cole

<div><div><div><p>Molecular mechanics force field parameters for macromolecules, such as proteins, are traditionally fit to reproduce experimental properties of small molecules, and thus they neglect system-specific polarization. In this paper, we introduce a complete protein force field that is designed to be compatible with the QUantum mechanical BEspoke (QUBE) force field by deriving non-bonded parameters directly from the electron density of the specific protein under study. The main backbone and sidechain protein torsional parameters are re-derived in this work by fitting to quantum mechanical dihedral scans for compatibility with QUBE non-bonded parameters. Software is provided for the preparation of QUBE input files. The accuracy of the new force field, and the derived torsional parameters, are tested by comparing the conformational preferences of a range of peptides and proteins with experimental measurements. Accurate backbone and sidechain conformations are obtained in molecular dynamics simulations of dipeptides, with NMR J coupling errors comparable to the widely-used OPLS force field. In simulations of five folded proteins, the secondary structure is generally retained and the NMR J coupling errors are similar to standard transferable force fields, although some loss of the experimental structure is observed in certain regions of the proteins. With several avenues for further development, the use of system-specific non-bonded force field parameters is a promising approach for next-generation simulations of biological molecules.</p></div></div></div>


2019 ◽  
Author(s):  
Alice Allen ◽  
Michael J. Robertson ◽  
Michael C. Payne ◽  
Daniel Cole

<div><div><div><p>Molecular mechanics force field parameters for macromolecules, such as proteins, are traditionally fit to reproduce experimental properties of small molecules, and thus they neglect system-specific polarization. In this paper, we introduce a complete protein force field that is designed to be compatible with the QUantum mechanical BEspoke (QUBE) force field by deriving non-bonded parameters directly from the electron density of the specific protein under study. The main backbone and sidechain protein torsional parameters are re-derived in this work by fitting to quantum mechanical dihedral scans for compatibility with QUBE non-bonded parameters. Software is provided for the preparation of QUBE input files. The accuracy of the new force field, and the derived torsional parameters, are tested by comparing the conformational preferences of a range of peptides and proteins with experimental measurements. Accurate backbone and sidechain conformations are obtained in molecular dynamics simulations of dipeptides, with NMR J coupling errors comparable to the widely-used OPLS force field. In simulations of five folded proteins, the secondary structure is generally retained and the NMR J coupling errors are similar to standard transferable force fields, although some loss of the experimental structure is observed in certain regions of the proteins. With several avenues for further development, the use of system-specific non-bonded force field parameters is a promising approach for next-generation simulations of biological molecules.</p></div></div></div>


Author(s):  
Joshua Horton ◽  
Alice Allen ◽  
Leela Dodda ◽  
Daniel Cole

<div><div><div><p>Modern molecular mechanics force fields are widely used for modelling the dynamics and interactions of small organic molecules using libraries of transferable force field parameters. For molecules outside the training set, parameters may be missing or inaccurate, and in these cases, it may be preferable to derive molecule-specific parameters. Here we present an intuitive parameter derivation toolkit, QUBEKit (QUantum mechanical BEspoke Kit), which enables the automated generation of system-specific small molecule force field parameters directly from quantum mechanics. QUBEKit is written in python and combines the latest QM parameter derivation methodologies with a novel method for deriving the positions and charges of off-center virtual sites. As a proof of concept, we have re-derived a complete set of parameters for 109 small organic molecules, and assessed the accuracy by comparing computed liquid properties with experiment. QUBEKit gives highly competitive results when compared to standard transferable force fields, with mean unsigned errors of 0.024 g/cm3, 0.79 kcal/mol and 1.17 kcal/mol for the liquid density, heat of vaporization and free energy of hydration respectively. This indicates that the derived parameters are suitable for molecular modelling applications, including computer-aided drug design.</p></div></div></div>


Author(s):  
Joshua Horton ◽  
Alice Allen ◽  
Leela Dodda ◽  
Daniel Cole

<div><div><div><p>Modern molecular mechanics force fields are widely used for modelling the dynamics and interactions of small organic molecules using libraries of transferable force field parameters. For molecules outside the training set, parameters may be missing or inaccurate, and in these cases, it may be preferable to derive molecule-specific parameters. Here we present an intuitive parameter derivation toolkit, QUBEKit (QUantum mechanical BEspoke Kit), which enables the automated generation of system-specific small molecule force field parameters directly from quantum mechanics. QUBEKit is written in python and combines the latest QM parameter derivation methodologies with a novel method for deriving the positions and charges of off-center virtual sites. As a proof of concept, we have re-derived a complete set of parameters for 109 small organic molecules, and assessed the accuracy by comparing computed liquid properties with experiment. QUBEKit gives highly competitive results when compared to standard transferable force fields, with mean unsigned errors of 0.024 g/cm3, 0.79 kcal/mol and 1.17 kcal/mol for the liquid density, heat of vaporization and free energy of hydration respectively. This indicates that the derived parameters are suitable for molecular modelling applications, including computer-aided drug design.</p></div></div></div>


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