Theoretical 3D electron diffraction electrostatic potential maps of proteins modeled with a multipolar pseudoatom...

Area of Science:

• Structural biology
• Computational chemistry
• Biophysics

Background:

• Atomic resolution experimental maps of electrostatic potential from 3D electron diffraction (3D ED) offer new insights.
• Accurate computational tools for macromolecular electrostatic potential are needed, avoiding expensive quantum calculations.

Purpose of the Study:

• To present and validate a computational method for calculating electrostatic potential maps of macromolecules.
• To compare theoretical calculations with experimental 3D ED data.

Main Methods:

• Application of the transferable aspherical atom model (TAAM) with the University at Buffalo Data Bank (UBDB).
• Calculation of electrostatic potential maps for lysozyme and proteinase K.
• Comparison of theoretical maps with experimental 3D ED maps.

Main Results:

• The UBDB model, using TAAM, provides a more accurate representation of molecular electrostatic potential than the independent atom model (IAM).
• Theoretical electron density maps were generated and compared with electrostatic potential maps.
• The influence of atomic displacement parameters (B factors) on electrostatic potential maps was investigated.

Conclusions:

• The presented computational method offers a cost-effective way to generate accurate electrostatic potential maps.
• This approach can aid in interpreting low-resolution cryo-electron microscopy data.
• Potential applications include distinguishing ions and water molecules in macromolecular active sites for drug design.