Copper is an essential trace element required for life. Due to its ability to access two oxidation states in the biological range, copper is utilised as an active cofactor for many proteins in a variety of processes including the production of ATP in the mitochondria and disposal of toxic oxygen radicals. However, free forms of copper are toxic to cells due to its reactivity with molecular oxygen. Thus, tight regulation of copper uptake and trafficking is essential to maintain copper homeostasis within the cells.

In eukaryotes, copper uptake into cells is mediated by copper transporters (Ctr) at the cell membrane. Ctr proteins are small integral membrane proteins, demonstrated to contain three transmembrane domains, an extracellular N-terminus and an intracellular C-terminus. The Ctr proteins have been shown to form oligomers and require metal binding motifs in the N-terminus and in the transmembrane region for function. To unveil the molecular mechanism of copper uptake through structural characterisation, Ctr1 from Saccharomyces cerevisiae has been cloned and overexpressed in its native system. Progress towards expression and purification will be presented.