Conformational Study of the PCU Cage Monopeptide: A Key Role of Some Force-Field Parameters

2009 ◽  
Vol 113 (15) ◽  
pp. 5234-5238
Author(s):  
Krishna Bisetty ◽  
Juan J. Perez
2013 ◽  
Vol 1526 ◽  
Author(s):  
F.O. Valega Mackenzie ◽  
B. J. Thijsse

ABSTRACTIn this work we report a specialized reactive force field (ReaxFF) developed for the study of alumina/epoxy interfaces. Force field parameters were obtained by fitting the reactions of small clusters and separate components of epoxies on alumina surfaces in the alpha phase. We also introduce a procedure to obtain crosslinked epoxies based on a proximity criterion to drive reactions and induce crosslinking. Properties of the resulting polymer, like the coefficient of thermal expansion, are found to be of the same order of magnitude as in experiments. Molecular dynamics was used to calculate the adhesion between these polymers and different alumina surfaces: Al2O3-deficient, Al-terminated, O-terminated, 12% and 75% hydroxylated. Typical values for strong adhesion are about 0.70 J/m2 which compare well with previously reported works. The role of defects is also studied.


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>


2002 ◽  
Vol 23 (6) ◽  
pp. 610-624 ◽  
Author(s):  
Nicolas Ferré ◽  
Xavier Assfeld ◽  
Jean-Louis Rivail

RSC Advances ◽  
2014 ◽  
Vol 4 (89) ◽  
pp. 48621-48631 ◽  
Author(s):  
Eleanor R. Turpin ◽  
Sam Mulholland ◽  
Andrew M. Teale ◽  
Boyan B. Bonev ◽  
Jonathan D. Hirst

2000 ◽  
Vol 104 (3-4) ◽  
pp. 247-251 ◽  
Author(s):  
Jacqueline Langlet ◽  
Jacqueline Berg�s ◽  
Jacqueline Caillet ◽  
Jiri Kozelka

2021 ◽  
Vol 200 ◽  
pp. 110759
Author(s):  
Rafikul Islam ◽  
Md Fauzul Kabir ◽  
Saugato Rahman Dhruba ◽  
Khurshida Afroz

2016 ◽  
Vol 56 (4) ◽  
pp. 811-818 ◽  
Author(s):  
Suqing Zheng ◽  
Qing Tang ◽  
Jian He ◽  
Shiyu Du ◽  
Shaofang Xu ◽  
...  

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