Mapping molecular electrostatic potential for heme interacting with nano metal oxides

Abstract

Interacting various living components with several materials in the gaseous nanoscale form has been of great concern as they are utilized in different life aspects. This work is conducted to assess the impact of interacting heme molecule, the main constituent of blood hemoglobin, with various common and non-common divalent molecules such as O2, CO2, CO, MgO, CoO, NiO, CuO and ZnO. Calculations are calculated at DFT high theoretical level using B3LYP/SDD method. In addition, molecular electrostatic potential (MESP) maps are constructed. Results demonstrate that interacting heme with proposed various structures lowers their energies reflecting more stability. However, the addition of non-familiar species to heme makes it more stable that may affect its transportation function for O2 and CO2 in the presence of these toxic materials in the gaseous state. The calculated TDM of the various proposed structures indicates that they are all more reactive than heme, since TDM of all of them are larger than that of pure heme. MESP maps show that extreme negative electrostatic regions are concentrated around C=O group of terminal carboxyl groups suggesting electrophilic interactions to take place there while positive regions are found around Fe central atom and on the circumference of all the proposed structures that are occupied by H atoms increasing the probability of nucleophilic reactions in these regions. Therefore, presence of such hazardous materials in the gaseous nanoscale may impact negatively the transportation function of heme.