Rusticyanin from <taxon tax_id="920">Thiobacillus ferrooxidans</taxon> is an electron carrier from cytochrome c-552 to the a-type oxidase. This protein belong to the family of type I blue copper proteins that are found in methylothropic bacteria, where they appear to function as the electron acceptor to methylamine dehydrogenase. The NMR structure indicates thefold to be a compact beta-barrel or beta-sandwich, which contains a hydrophobic core rich in aromatic residues [<cite idref="PUB00003339"/>]. Its sequence is highly diverged from related copper-blue proteins, but it has a similar active site, containing conserved His and Cys residues responsible for bindingcopper. Rusticyanin