Scheme 1. Reaction Scheme Based on the Functional (40) and Conformational (this paper) Characterization of T. maritima CopA.

The enzyme can be phosphorylated by either ATP or P_i in the absence of copper, yielding E_b-P undergoing slow turnover. However, the active (E_a) conformation undergoing fast turnover is only obtained following binding of Cu⁺ to both NMBD and TMBS. Interaction of NMBD with the catalytic headpiece and A domain movements play important roles in the sequential reactions of the fast cycle. It is possible that the copper occupancy of the NMBD remains throughout the cycle, while copper bound to the TMBS is released within each cycle. See Discussion.