Presentation Title

Substituent effects on electrostatic potential maps of calcium cage models

Faculty Mentor

Dr. Alison McCurdy

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

CREVELING 33

Session

POSTER 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Despite many investigations in oscillatory Ca2+ signaling, important aspects remain unclear. To address this need, a photo-reversible calcium cage was designed and synthesized to controllably bind and release calcium ions. To improve the ability to mimic physiological calcium binding, current studies are focused on enhancing the calcium binding affinity through the addition of methoxy substituents. Due to the electron-donating behavior of methoxy groups, it is hypothesized that the dianisole substituents will increase the electron density at the calcium-binding site, thus increasing the calcium affinity of the open form. In this study we investigated the substituent effects on electrostatic potential maps of various stereoisomers of a model photo-reversible calcium ligand at the B3LYP/6-31G(d,p) level of theory. Computational results indicate that the presence of methoxy groups decreases the electrostatic potential energy (makes more negative) at the calcium binding oxygen atom by 7.72 kJ/mol and 6.52 kJ/mol in water and vacuum, respectively, relative to the previous diphenyl model. Further findings show that the calcium ligand’s configuration also influences the electron density at the chelating oxygen atom. Lastly, the effects of solvation suggest that the polar solvent water decreases the electrostatic potential energy at the calcium-binding oxygen relative to vacuum. The quantitative relationship between electrostatic potential and the calcium binding affinity has not yet been determined.

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Nov 17th, 12:30 PM Nov 17th, 2:30 PM

Substituent effects on electrostatic potential maps of calcium cage models

CREVELING 33

Despite many investigations in oscillatory Ca2+ signaling, important aspects remain unclear. To address this need, a photo-reversible calcium cage was designed and synthesized to controllably bind and release calcium ions. To improve the ability to mimic physiological calcium binding, current studies are focused on enhancing the calcium binding affinity through the addition of methoxy substituents. Due to the electron-donating behavior of methoxy groups, it is hypothesized that the dianisole substituents will increase the electron density at the calcium-binding site, thus increasing the calcium affinity of the open form. In this study we investigated the substituent effects on electrostatic potential maps of various stereoisomers of a model photo-reversible calcium ligand at the B3LYP/6-31G(d,p) level of theory. Computational results indicate that the presence of methoxy groups decreases the electrostatic potential energy (makes more negative) at the calcium binding oxygen atom by 7.72 kJ/mol and 6.52 kJ/mol in water and vacuum, respectively, relative to the previous diphenyl model. Further findings show that the calcium ligand’s configuration also influences the electron density at the chelating oxygen atom. Lastly, the effects of solvation suggest that the polar solvent water decreases the electrostatic potential energy at the calcium-binding oxygen relative to vacuum. The quantitative relationship between electrostatic potential and the calcium binding affinity has not yet been determined.