Abstract
Nitric oxide (NO) and nitroxyl (HNO) have important roles in numerous biological processes. Both NO and HNO target and are a part of common biological mechanisms by reacting with heme proteins, among others, via unique and distinct chemistry. Herein, the binding of NO and HNO to the ferrous heme in myoglobin (Mb) and Mb variants is investigated to elucidate the vibrational properties of heme-HNO complexes in detail. Initially, the expression and purification of Sperm Whale myoglobin and variants was accomplished, and these proteins were then utilized to generate both ferrous heme-nitrosyl and -nitroxyl complexes under anaerobic conditions. All complexes were characterized using UV-visible, electron paramagnetic resonance (EPR), and nuclear magnetic resonance (NMR) spectroscopy, and nuclear resonance vibrational spectroscopy (NRVS) at SPring-8. The ongoing investigation will give further insight into the electronic structure of ferrous heme-nitrosyl and -nitroxyl complexes to shed light on the common and district biological mechanisms of NO and HNO.
