An Ancient Pathway Combining Carbon Dioxide Fixation with the Generation and Utilization of a Sodium Ion Gradient for ATP Synthesis

作者：Poehlein Anja^*; Schmidt Silke; Kaster Anne Kristin; Goenrich Meike; Vollmers John; Thuermer Andrea; Bertsch Johannes; Schuchmann Kai; Voigt Birgit; Hecker Michael; Daniel Rolf; Thauer Rudolf K; Gottschalk Gerhard; Mueller Volker

来源：PLos One, 2012, 7(3): e33439.

DOI：10.1371/journal.pone.0033439

Synthesis of acetate from carbon dioxide and molecular hydrogen is considered to be the first carbon assimilation pathway on earth. It combines carbon dioxide fixation into acetyl-CoA with the production of ATP via an energized cell membrane. How the pathway is coupled with the net synthesis of ATP has been an enigma. The anaerobic, acetogenic bacterium Acetobacterium woodii uses an ancient version of this pathway without cytochromes and quinones. It generates a sodium ion potential across the cell membrane by the sodium-motive ferredoxin:NAD oxidoreductase (Rnf). The genome sequence of A. woodii solves the enigma: it uncovers Rnf as the only ion-motive enzyme coupled to the pathway and unravels a metabolism designed to produce reduced ferredoxin and overcome energetic barriers by virtue of electron-bifurcating, soluble enzymes.

• 出版日期2012-3-29