Structure and function of ATP synthases from homoacetogenic bacteria and methanogenic archaea

点击翻译按钮获取中文摘要

ATPases are multisubunit, membrane-bound enzymes with two functional domains; they are present in all organisms and have derived from a common ancestor. Our knowledge about the structure and function of the ATPases increased considerably during recent years but it still is restricted to a limited number of catalytic and structural aspects delineated for a few paradigms only. The biochemical and molecular analyses of enzymes from other sources with different properties than the paradigms will contribute significantly to our understanding of structure, reaction mechanism and functional evolution of these enzymes. From the anaerobic bacterium Acetobacterium woodii we have isolated a F-type ATPase with altered ion specificity, i. e. Na+ instead of H+, and a unique subunit composition. In addition, from methanogenic archaea we have characterized ATPases which turned out to be very unique with respect to subunit composition and function. The encoding genes of all these ATPases were cloned and sequenced. Future work is aimed to elucidate the function of the individual subunits in catalysis, the path of ion flow through the membrane, and the coupling of ion flow to ATP hydrolysis/synthesis; main emphasis will be on structure determinations.