K+/Na+ selectivity by experiment and calculation
| Method | Solvent | ΔΔG (kcal/mol) | Selective for |
| Experiment | Formamidea | −0.9 | Na+ |
| Formamidebc | −0.7 | Na+ | |
| NMAbd | −1.1 | Na+ | |
| Pairwise Additive | Formamidec | 0.9 | K+ |
| (CHARMM27) | |||
| Formamidec | 1.3 | K+ | |
| (OPLS-AA) | |||
| NMAe | 1.6 | K+ | |
| (CHARMM22/NBFIX) | |||
| NMAdg | 0.7* | K+ | |
| (CHARMM27) | |||
| NMAdg | 2.6* | K+ | |
| (CHAEMM27/NBFIX) | |||
| Polarizable | Formamidec | −1.3 | Na+ |
| (AMOEBA) | |||
| Formamidef | −2.2 | Na+ | |
| (QM/MM) | |||
| NMAd | −0.3 | Na+ | |
| (Drude) |
| Method | Solvent | ΔΔG (kcal/mol) | Selective for |
| Experiment | Formamide | −0.9 | Na+ |
| Formamide | −0.7 | Na+ | |
| NMA | −1.1 | Na+ | |
| Pairwise Additive | Formamide | 0.9 | K+ |
| (CHARMM27) | |||
| Formamide | 1.3 | K+ | |
| (OPLS-AA) | |||
| NMA | 1.6 | K+ | |
| (CHARMM22/NBFIX) | |||
| NMA | 0.7* | K+ | |
| (CHARMM27) | |||
| NMA | 2.6* | K+ | |
| (CHAEMM27/NBFIX) | |||
| Polarizable | Formamide | −1.3 | Na+ |
| (AMOEBA) | |||
| Formamide | −2.2 | Na+ | |
| (QM/MM) | |||
| NMA | −0.3 | Na+ | |
| (Drude) |
K+/Na+ selectivity of bulk liquid formamide and NMA as determined by experimental work, pairwise-additive (nonpolarizable) force field calculation, polarizable force field (AMOEBA and Drude) calculations, and QM/MM (hybrid quantum mechanical and molecular mechanical) calculations. Note that the pairwise-additive force field calculations display positive (K+) selectivity, whereas all other determinations display negative (Na+) selectivity.
Marcus, 1983.
Cox and Parker, 1973, and Schmid et.al., 2000.
Grossfield et al., 2003.
Yu et al., 2010a
Noskov et al., 2004.
Varma and Rempe, 2008.
Noskov and Roux, 2008.
Sharing content requires targeting cookies to be enabled. Please update your cookie preferences to use this feature.