Mössbauer spectroscopy as a probe of electric field in heme pocket of deoxyheme proteins: theoretical approach

Chemical reactions taking place in active centers of different enzymes are controlled by electric fields created by the protein in these centers. These electric fields can be experimentally detected by different experimental techniques (infrared absorption, NMR, etc.). In this paper, we use quantum chemical calculations to show that Mössbauer spectroscopy can be also used to study protein electric field. We study effect of both the model and protein electric fields on the magnitude of quadrupole splitting of Mössbauer spectra of the high-spin ferrous myoglobin and its models. It is shown that the quadrupole splitting is notably affected by the protein electric field. This result also explains a number of the experimental data.