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

ATP酶是多亚基的膜结合酶，具有两个功能结构域;它们存在于所有生物体中，并且来自共同的祖先。近年来，我们对ATP酶的结构和功能的了解大大增加，但仍然局限于有限的催化和结构方面，仅限于少数几个范例。对其他来源的具有不同性质的酶进行生物化学和分子生物学分析，将有助于我们对这些酶的结构、反应机制和功能进化的理解。从厌氧细菌Acetobacterium woodii中分离到一种离子特异性改变的F型ATP酶，即：e. Na+而不是H+，以及独特的亚基组成。此外，从产甲烷古菌，我们的特点是ATP酶，原来是非常独特的亚基组成和功能。对所有这些ATP酶的编码基因进行了克隆和序列测定。未来的工作旨在阐明催化中各个亚基的功能，离子流通过膜的路径，以及离子流与ATP水解/合成的耦合;主要重点将是结构测定。

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.