The electronic structure of human erythropoietin as an aid in the design of oxidation-resistant therapeutic proteins

The electronic structure of human erythropoietin (HuEPO) has been investigated with the aid of quantum mechanical calculations. The results indicate that the protein is highly polarized and its permanent dipole moment has a magnitude of 471 D. The HOMO of HuEPO is localized on Trp51, which stays in close proximity to Met54. Three oxidation-resistant mutants of HuEPO (W51F, M54V, and W51F-M54V) have been modeled and their electronic structures are compared to that of the native protein. Among them, the W51F mutation is predicted to be the most effective in increasing the oxidation potential of the protein.