2019/04/04 by Muhamed Amin, Amin, Muhamed, Hebatallah Samy +3
Biochemistry, Genetics and Molecular Biology · #Advanced Electron Microscopy Techniques and Applications #Advanced Fluorescence Microscopy Techniques #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Spectroscopy Techniques in Biomedical and Chemical Research
paper · pdf · doi:10.48550/arxiv.1904.02504
openalex publication_date 2019/04/04 · openalex created_date 2022/07/24 · openalex updated_date 2026/07/28
Alignment of molecules through electric fields minimizes the averaging over\norientations, e. g., in single particle imaging experiments. The response of\nmolecules to external ac electric fields is governed by their polarizability\ntensor, which is usually calculated using quantum-chemistry methods. These\nmethods are not feasible for large molecules. Here, we calculate the\npolarizability tensor of proteins using a regression model that correlates the\npolarizabilities of the 20 amino acids with perfect conductors of the same\nshape. The dielectric constant of the molecules could be estimated from the\nslope of the regression line based on Clausius Mossotti equation. We benchmark\nour predictions against the quantum chemistry results for the Trp cage mini\nprotein and the measured dielectric constants of larger proteins. Our method\nhas applications in computing laser-alignment of macromolecules, for instance,\nbenefiting single particle imaging, as well as for the estimation of the\noptical and electrostatic characteristics of proteins and other macromolecules.\n