TY  - JOUR
A1  - Biegel, Eva
A1  - Müller, Volker
T1  - A Na+-translocating pyrophosphatase in the acetogenic bacterium Acetobacterium woodii
T2  - Journal of biological chemistry
N2  - The anaerobic acetogenic bacterium Acetobacterium woodii employs a novel type of Na+-motive anaerobic respiration, caffeate respiration. However, this respiration is at the thermodynamic limit of energy conservation, and even worse, in the first step, caffeate is activated by caffeyl-CoA synthetase, which hydrolyzes ATP to AMP and pyrophosphate. Here, we have addressed whether or not the energy stored in the anhydride bond of pyrophosphate is conserved by A. woodii. Inverted membrane vesicles of A. woodii have a membrane-bound pyrophosphatase that catalyzes pyrophosphate hydrolysis at a rate of 70–120 milliunits/mg of protein. Pyrophosphatase activity was dependent on the divalent cation Mg2+. In addition, activity was strictly dependent on Na+ with a Km of 1.1 mm. Hydrolysis of pyrophosphate was accompanied by 22Na+ transport into the lumen of the inverted membrane vesicles. Inhibitor studies revealed that 22Na+ transport was primary and electrogenic. Next to the Na+-motive ferredoxin:NAD+ oxidoreductase (Fno or Rnf), the Na+-pyrophosphatase is the second primary Na+-translocating enzyme in A. woodii.
KW  - Bacterial Metabolism
KW  - Bioenergetics
KW  - Electron Transport
KW  - Energy Metabolism
KW  - Membrane Enzymes
KW  - Acetobacterium
KW  - Na Gradient
KW  - Caffeate Respiration
KW  - Energy Conservation
KW  - Pyrophosphatase
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/76560
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-765601
SN  - 0021-9258
VL  - 286
IS  - 8
SP  - 6080
EP  - 6084
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -