Table 1.
Summary of strictly conserved His residues with corresponding pKa shifts, ΔΔG, and interaction partners in different alphaviruses
| H-bond interaction partners | M→FI | FI→Dis/HT | ||||||
| Residue | M | FI | HT/Dis | ΔpKa | −ΔΔG | ΔpKa | −ΔΔG | Domain interface* |
| H3(E1) | PCP(E1)† | PCP (E1) | E284/F287(E1/E1′)‡ | −0.1 | 0.0 | 2.6 | 2.2 | HT: DI/DIII′ |
| H125(E1) | T126(E1′) | T126 (E1′) | D174(E1′) | 0.4 | 0.3 | 2.2 | 1.8 | HT: DII/DII′ |
| H230(E1) | R267(E2′) | R267 (E2′) | E67(E1′) | −1.5 | 0.0 | 3.9 | 0.8 | HT: DII/DII′ |
| H331(E1) | PCP(E1) | PCP (E1) | N149(E1′) | −1.0 | 0.1 | 5.0 | 2.7 | HT: DIII/DI′ |
| H386(E1) | K280(E2) | K280(E2) | F192(E1′) | 0.1 | 0.1 | 1.1 | 1.0 | E2–E1: DC/stem |
| H170(E2) | S57(E1)/R244(E2) | — | — | 1.1 | 1.0 | −0.8 | −0.7 | E2–E1: β/DII |
| H256(E2) | K254(E2) | K254(E2) | K254/E166(E2) | −0.1 | −0.1 | 0.4 | 0.4 | — |
*
Domain interface of the relative stronger interaction is listed.
†
PCP, positively charged pocket composed of Y15(E1), K16(E1), and T17(E1).
‡
E1′ refers to another E1 protein belonging to the nearest monomeric or dimeric neighbor interacting with the protein of focus.