pKa Prediction

Knowing the pKa of a molecule is key to understanding its structure and reactivity. Rowan's pKa prediction workflow uses machine-learned interatomic potentials and semiempirical solvation energies to enable fast and accurate prediction of pKa values with minimal empiricism.

How It Works

The full Rowan pKa workflow is explained in our preprint. Here's a high-level visual overview:

"An overview of how Rowan predicts pKa values"
"An overview of how Rowan predicts pKa values"

Accuracy

On a variety of benchmarks (also described in the preprint), Rowan pKa displays mean absolute errors of around 1 pKa unit, and decent predictive accuracy as assessed by Kendall's Ï„ and r2 values. Here's the performance on the SAMPL7 benchmark set:

"Our performance on SAMPL7"
"Our performance on SAMPL7"

For a full list of all assays surveyed, see the preprint.

Modes

Rowan pKa can be run in three modes: careful, rapid, or reckless. Here's what selecting each mode tunes:

ModeCarefulRapidReckless
buffer around desired range (pKa units)1055
number of initial conformations25010050
initial energy cutoff (kcal/mol)15105
RMSD similarity cutoff (Ã…)0.100.250.50
max number of conformers (xTB)20103
final energy cutoff (kcal/mol)553
max number of conformers (AIMNet2)1031

In general, we've found that the "careful" mode offers the best combination of speed and accuracy, but faster modes offer increased performance where high throughput is required.