14 Spectroscopic NMR Characterizations of HNO Adducts of Ferrous Heme Proteins
 

14 Spectroscopic NMR Characterizations of HNO Adducts of Ferrous Heme Proteins

Publication date: 2017
Source:The Chemistry and Biology of Nitroxyl (HNO)</br>
Author(s): M.R. Kumar, P.J. Farmer</br>
HNO reacts with the ferrous states of many heme proteins such as myoglobin and hemoglobin to form stable HNO-Fe(II) adducts. Like the analogous O2 adducts, the HNO adducts are diamagnetic, but with a characteristic HNO resonance in 1H NMR c.15ppm that splits into doublets for H15NO adducts. As an illustration, we discuss HNO adducts of several heme-pocket mutants of myoglobin, hemoglobins, and related heme proteins. The 1H and 15N NMR resonances, obtained by HSQC experiments, are shown to differentiate subunits and isoforms of proteins within mixtures. NMR characterizations of these HNO adducts is a unique tool that is a sensitive to structural changes within the oxygen-binding cavity, which we suggest may help define modes of oxygen binding and activation in other heme enzymes.
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