Structure, function, and evolution of respiratory proteins

Abstract

Respiratory proteins are complexes of proteins and metal ions. In haemoglobin the metal is iron, in haemocyanin—the most common invertebrate respiratory protein—it is copper. Globins such as haemoglobin and myoglobin and related molecular complexes have probably been around as long as life itself, whereas others such as the most common respiratory protein of molluscs and arthropods, haemocyanin, appear to be younger and are not chemically related to globins. Nevertheless, astounding functional similarities between haemoglobin and haemocyanin are seen. The present chapter takes a look at the molecular mechanisms behind their function, their fundamental integration in the respiratory process, and also traces the evolution of these respiratory proteins.