Mikrobiologie, Fakultät Biologie, Universität Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany.
Nature. 2010 Apr 15;464(7291):1077-81. doi: 10.1038/nature08884. Epub 2010 Mar 28.
Most archaeal groups and deeply branching bacterial lineages harbour thermophilic organisms with a chemolithoautotrophic metabolism. They live at high temperatures in volcanic habitats at the expense of inorganic substances, often under anoxic conditions. These autotrophic organisms use diverse carbon dioxide fixation mechanisms generating acetyl-coenzyme A, from which gluconeogenesis must start. Here we show that virtually all archaeal groups as well as the deeply branching bacterial lineages contain a bifunctional fructose 1,6-bisphosphate (FBP) aldolase/phosphatase with both FBP aldolase and FBP phosphatase activity. This enzyme is missing in most other Bacteria and in Eukaryota, and is heat-stabile even in mesophilic marine Crenarchaeota. Its bifunctionality ensures that heat-labile triosephosphates are quickly removed and trapped in stabile fructose 6-phosphate, rendering gluconeogenesis unidirectional. We propose that this highly conserved, heat-stabile and bifunctional FBP aldolase/phosphatase represents the pace-making ancestral gluconeogenic enzyme, and that in evolution gluconeogenesis preceded glycolysis.
大多数古菌群体和深分支细菌谱系都拥有嗜热的化能自养生物，它们以无机物质为食，在高温的火山环境中生活，通常处于缺氧条件下。这些自养生物使用多种二氧化碳固定机制产生乙酰辅酶 A，而糖异生必须从乙酰辅酶 A 开始。在这里，我们发现实际上所有的古菌群体以及深分支细菌谱系都含有一种具有果糖 1,6-二磷酸（FBP）醛缩酶/磷酸酶双重活性的双功能果糖 1,6-二磷酸（FBP）醛缩酶/磷酸酶。这种酶在大多数其他细菌和真核生物中都不存在，并且在嗜热的海洋泉古菌中也很耐热。它的双功能确保了不稳定的三磷酸丙糖迅速被去除并被稳定的果糖 6-磷酸捕获，使糖异生单向进行。我们提出，这种高度保守、耐热和双功能的 FBP 醛缩酶/磷酸酶代表了原始的糖异生酶，并且在进化过程中糖异生先于糖酵解。
