Evolution of proteins formed by β-sheets

摘要: Abstract Plastocyanin and azurin form a family of small copper-containing proteins, active in the electron transport systems plants bacteria, respectively. The crystal structures two members this have been determined: poplar leaf plastocyanin Pseudomonas aeruginosa azurin. Both proteins contain β-sheets, packed face-to-face. Using computed superpositions structures, we aligned sequences, identified homologous positions, studied how changed as result mutations. residues vicinity copper-binding site show minimal amino acid substitution almost identical structures. Other portions these are more variable sequence structure. Buried tend to maintain their hydrophobic character, but mutations change volume. mean variation volume buried is 54 A3. differences size shape accommodated by 3.8 A shift relative position β-sheets. This does not affect copper binding site, because that in, or adjacent to, just one