Quantum chemical modeling of mutation-induced amino acid substitutions in the copper-binding site of azurin

Inclusion of Cu ions, along with ions of other d-elements with variable valences, from water-soluble low-molecular complexes into precursor protein structures is thought to be one of the most important stages of evolutionary processes on Earth. Due to reversible changes in the valence of metal ions, the newly formed bio clusters considerably diversified and intensified various biochemical processes: redox reactions, transport of metabolic intermediates, generation and inactivation of oxygen radicals, synthesis of high-energy compounds, etc. The efficient functioning of copper protein complexes is evidenced by their extremely early (at least 3 milliard years ago) formation as rather conservative structures, as well as by their widest distribution among bacteria, archaea and eukaryotes.