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.
The full Rowan pKa workflow is explained in our preprint. Here's a high-level visual overview:
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:
For a full list of all assays surveyed, see the preprint.
Rowan pKa can be run in three modes: careful, rapid, or reckless. Here's what selecting each mode tunes:
Mode | Careful | Rapid | Reckless |
---|---|---|---|
buffer around desired range (pKa units) | 10 | 5 | 5 |
number of initial conformations | 250 | 100 | 50 |
initial energy cutoff (kcal/mol) | 15 | 10 | 5 |
RMSD similarity cutoff (Ã…) | 0.10 | 0.25 | 0.50 |
max number of conformers (xTB) | 20 | 10 | 3 |
final energy cutoff (kcal/mol) | 5 | 5 | 3 |
max number of conformers (AIMNet2) | 10 | 3 | 1 |
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.