2lln is a 1 chain structure with sequence from Thermus thermophilus. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
COX2_THETH Subunits I and II form the functional core of the enzyme complex. Electrons originating in cytochrome c are transferred via heme a and Cu(A) to the binuclear center formed by heme a3 and Cu(B).