Electronic Polarization Effects upon Charge Injection in Oligoacene Molecular Crystals: Description via a Polarizable Force Field

<div>Methylguanidinium is an important molecular ion which also serves as the model compound for arginine side chain. We studied the structure and dynamics of methylguanidium ion at the air/water interface by molecular dynamics simulations employing the Drude polarizable force field. We found out that methylguanidinium accumulate on the interface with a majority adopting tilted conformations. We also demonstrated that methylguanidinium and guanidinium ions have different preference towards the air/water interface. Our results illustrate the importance to explicitly include the electronic polarization effects in modeling interfacial properties.</div><div><br> </div>

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Methylguanidinium at the Air/Water Interface: A Simulation Study with the Drude Polarizable Force Field

10.26434/chemrxiv.12973178 ◽

2020 ◽

Author(s):

Jian Zhu ◽

Jing Huang

Keyword(s):

Force Field ◽

Model Compound ◽

Side Chain ◽

Water Interface ◽

Polarizable Force Field ◽

Polarization Effects ◽

Structure And Dynamics ◽

Arginine Side Chain ◽

Air Water Interface ◽

Dynamics Simulations

<div>Methylguanidinium is an important molecular ion which also serves as the model compound for arginine side chain. We studied the structure and dynamics of methylguanidium ion at the air/water interface by molecular dynamics simulations employing the Drude polarizable force field. We found out that methylguanidinium accumulate on the interface with a majority adopting tilted conformations. We also demonstrated that methylguanidinium and guanidinium ions have different preference towards the air/water interface. Our results illustrate the importance to explicitly include the electronic polarization effects in modeling interfacial properties.</div><div><br> </div>

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Methylguanidinium at the Air/Water Interface: A Simulation Study with the Drude Polarizable Force Field

10.26434/chemrxiv.12973178.v1 ◽

2020 ◽

Author(s):

Jian Zhu ◽

Jing Huang

Keyword(s):

Force Field ◽

Model Compound ◽

Side Chain ◽

Water Interface ◽

Polarizable Force Field ◽

Polarization Effects ◽

Structure And Dynamics ◽

Arginine Side Chain ◽

Air Water Interface ◽

Dynamics Simulations

<div>Methylguanidinium is an important molecular ion which also serves as the model compound for arginine side chain. We studied the structure and dynamics of methylguanidium ion at the air/water interface by molecular dynamics simulations employing the Drude polarizable force field. We found out that methylguanidinium accumulate on the interface with a majority adopting tilted conformations. We also demonstrated that methylguanidinium and guanidinium ions have different preference towards the air/water interface. Our results illustrate the importance to explicitly include the electronic polarization effects in modeling interfacial properties.</div><div><br> </div>

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Ion Transport, Selectivity, and Electronic Polarization in Fluoride Channels

10.1101/2021.12.08.471811 ◽

2021 ◽

Author(s):

Zhi Yue ◽

Zhi Wang ◽

Gregory A Voth

Keyword(s):

Force Field ◽

Sampling Methods ◽

Molecular Level ◽

Electronic Polarization ◽

Conserved Residues ◽

Polarizable Force Field ◽

Constant Ph ◽

Free Energy Sampling ◽

Charged Form ◽

Constant Ph Molecular Dynamics

Fluoride channels (Fluc) export toxic F- from the cytoplasm. Crystallography and mutagenesis have identified several conserved residues crucial for fluoride transport, but the transport mechanism at the molecular level has remained elusive. Herein we have applied constant-pH molecular dynamics and free energy sampling methods to investigate fluoride transfer through a Fluc protein from Escherichia coli. We find that fluoride is facile to transfer in its charged form, i.e., F-, by traversing through a non-bonded network. The extraordinary F- selectivity is gained by the hydrogen-bonding capability of the central binding site and the Coulombic filter at the channel entrance. The F- transfer rate calculated using an electronically polarizable force field is significantly more accurate compared to the experimental value than that calculated using a more standard additive force field, suggesting an essential role for electronic polarization in the F- - Fluc interactions.

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