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

atp酶是具有两个功能域的多亚基膜结合酶；它们存在于所有生物体中，并且起源于一个共同的祖先。近年来，我们对atp酶的结构和功能的了解大大增加，但它仍然局限于有限数量的催化和结构方面，仅为几个范例所描绘。对不同性质的酶进行生化和分子分析，将有助于我们进一步了解这些酶的结构、反应机理和功能演化。从厌氧细菌乙杆菌woodii中，我们分离出一种具有改变离子特异性的f型atp酶，即Na+而不是H+，并且具有独特的亚基组成。此外，从产甲烷的古菌中，我们已经表征了atp酶，这些atp酶在亚基组成和功能方面非常独特。对所有atp酶的编码基因进行了克隆和测序。未来的工作旨在阐明单个亚基在催化中的功能，离子流过膜的路径，以及离子流动与ATP水解/合成的耦合；主要的重点将放在结构的确定上。

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.