Table 3 Cation-Ï€ interaction energies between histidine (His) and cations in three solvents (water, acetonitrile, and cyclohexane)
From: The multiple roles of histidine in protein interactions
|  | Water (ε=78.39) | Acetonitrile (ε=35.9) | Cyclohexane (ε=2.0) | |||
|---|---|---|---|---|---|---|
Cation–His | Energy a | Length b | Energy | Length | Energy | Length |
Na+ | −0.262 | 3.556 | −0.182 | 3.536 | −3.145 | 2.777 |
K+ | −0.019 | 4.007 | −0.160 | 3.996 | −5.433 | 3.120 |
Ca++ | +0.087 | 3.835 | −0.568 | 3.797 | −8.898 | 2.582 |
Zn2+ | +0.009 | 3.835 | −0.828 | 2.885 | −41.442 | 2.115 |
Lys(CH3NH3+) | −0.391 | 3.961 | −0.324 | 3.944 | −2.310 | 3.245 |
Arg(CHN2NH2+) | −0.858 | 4.148 | −0.842 | 4.133 | −3.938 | 3.979 |
His+–π |  |  |  |  |  |  |
Phe | −0.602 | 2.499 | −0.965 | 2.493 | −3.429 | 2.305 |
Tyr | −0.884 | 2.511 | −0.924 | 2.505 | −3.421 | 2.299 |
Trp | −1.368 | 2.412 | −1.512 | 2.401 | −6.679 | 2.203 |