Determination of the electronic structure of proteins by quantum mechanics for discovery of new biological function

借助量子力学计算，我们探索了几种蛋白质的电子结构，并对它与生物功能的关系有了新的认识。膜蛋白如Kcsa钾通道、氯离子通道和捕光LH 2复合物的特征在于具有非常大的偶极矩（500~1000德拜）。这意味着膜内的蛋白质是强烈极化的。这种电荷的极化与生物功能有关。例如，强极化可用于保持恒定的离子通过膜的通量。此外，这些蛋白质的大偶极矩对于帮助较小的蛋白质如Charybdotoxin在与膜蛋白相互作用时采取正确的方向是重要的。最后，硫亚胺键，一种新型的化学键内的蛋白质（胶原蛋白IV）已被调查，其性质已被揭示使用量子力学计算。

With the aid of quantum mechanical calculations, we have explored the electronic structure of several proteins and obtained new insights about its relation with biological function. Membrane proteins such as the Kcsa potassium channel, the chloride channel, and the light-harvesting LH2 complex are characterized by very large dipole moments (500～1000 Debye). This means that the protein inside the membrane is strongly polarized. This polarization of charge is connected to biological function. For example, strong polarization may be useful to maintain constant the flux of ions through the membrane. Furthermore, the large dipole moment of these proteins is important on helpin smaller proteins like charybdotoxin to adopt the correct orientation when they interact with membrane proteins. Finally, the sulfilimine bond, a new type of chemical bonding inside proteins (collagen IV) has been investigated and its properties have been revealed using quantum mechanical calculations.