Pcetk: A pDynamo-based Toolkit for Protonation State Calculations in Proteins

Area of Science:

• Computational Biology
• Biophysics
• Structural Bioinformatics

Background:

• Calculating proton binding energetics in proteins is crucial for understanding their function.
• Estimating pKa values for protein groups and bound ligands can be experimentally challenging.

Purpose of the Study:

• To introduce Pcetk, an open-source toolkit for protein proton binding energetics.
• To provide a modern, extensible environment for calculating protonation states and electrostatic properties.
• To complement Pcetk with a validated computational method for estimating pKa values.

Main Methods:

• Developed Pcetk as a module of the pDynamo software library.
• Integrated pDynamo with the extended-MEAD Poisson-Boltzmann solver.
• Revisited and applied a computational method for estimating pKa values in aqueous solution.

Main Results:

• Pcetk enables calculation of protonation states, electrostatic energies, and titration curves.
• The integrated method for pKa estimation achieves accuracy of ± 0.5 pKa-units or better.
• Pcetk and the pKa estimation method were verified using model cases.

Conclusions:

• Pcetk offers a versatile and efficient platform for studying protein electrostatics.
• The combined toolkit and pKa estimation method address limitations in experimental pKa determination.
• This work provides valuable computational tools for researchers in structural biology and biophysics.