Rusticyanin

Abstract

Rusticyanin is a type 1 blue copper protein that functions as the major electron carrier in the iron respiratory electron transport chain of Thiobacillus ferrooxidans . This bacterium is the main cause of acid mine drainage. Rusticyanin is an extremophilic protein with redox activity as low as pH 0.5 and a redox potential of 680 mV, which is at least twice as high as for any other member of the family of cupredoxins. The ligands to the single copper ion are His85, Cys138, His143, and Met148. The three‐dimensional structure consists of a β‐sandwich of two mixed β‐sheets, one of six and one of seven strands, as well as a single amphipathic helix near the N‐terminus.