Bioenergetics of archaea: ancient energy conserving mechanisms developed in the early history of life.

A key component in cellular bioenergetics is the ATP synthase. The enzyme from archaea represents a new class of ATPases, the A1AO ATP synthases. They are composed of two domains that function as a pair of rotary motors connected by a central and peripheral stalk(s). The structure of the chemically-driven motor (A1) was solved by small angle X-ray scattering in solution, and the structure of the first A1AO ATP synthases (from methanoarchaea) was obtained recently by single particle analyses. These studies revealed novel structural features such as a second peripheral stalk and a collar-like structure. Interestingly, the membrane-embedded electrically-driven motor (AO) is very different in archaea with sometimes novel, exceptional subunit composition.