AUTHOR=Gorbikova Elena , Kalendar Ruslan 

TITLE=Comparison Between O and OH Intermediates of Cytochrome c Oxidase Studied by FTIR Spectroscopy

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00387

DOI=10.3389/fchem.2020.00387

ISSN=2296-2646

ABSTRACT=<p>Cytochrome <italic>c</italic> oxidase is terminal enzyme in the respiratory chain of mitochondria and many aerobic bacteria. It catalyzes reduction of oxygen to water. During its catalysis, C<italic>c</italic>O proceeds through several quite stable intermediates (<bold>R</bold>, <bold>A</bold>, <bold>PR/M</bold>, <bold>O/OH</bold>, <bold>E/EH</bold>). This work is concentrated on the elucidation of the differences between structures of oxidized intermediates <bold>O</bold> and <bold>O</bold><sub><bold>H</bold></sub> in different C<italic>c</italic>O variants and at different pH values. Oxidized intermediates of wild type and mutated C<italic>c</italic>O from <italic>Paracoccus denitrificans</italic> were studied by means of static and time-resolved Fourier-transform infrared spectroscopy in acidic and alkaline conditions in the infrared region 1800–1000 cm<sup>−1</sup>. No reasonable differences were found between all variants in these conditions, and in this spectral region. This finding means that the binuclear center of oxygen reduction keeps a very similar structure and holds the same ligands in the studied conditions. The further investigation in search of differences should be performed in the 4000–2000 cm<sup>−1</sup> IR region where water ligands absorb.</p>