English: Cytochrome c oxidase is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes. This enzyme responsible for the principal reaction carried out in the respiratory electron transport chain of cells. It receives four electrons and transfers them to the oxygen molecule and four protons, producing two molecules of water. The video shows part of the molecule of the cytochrome oxidase’s (subunit I) found in the slime mold Lycogala epidendrum (NCBI GenBank ON931582). Model was made in Phyre2 and visualized in EzMol 2.1. Red color shows the part of the molecule, studied in Myxomycetes. Colors indicate type of amino acids: yellow − neutral, green − polar uncharged, red − positive, blue − negative, lilac − aromatic.