An intracellular pH gradient in the anammox bacterium Kuenenia stuttgartiensis as evaluated by 31P NMR.
The cytoplasm of anaerobic ammonium oxidizing (anammox) bacteria consists of three compartments separated by membranes. It has been suggested that a proton motive force may be generated over the membrane of the innermost compartment, the "anammoxosome". 31P nuclear magnetic resonance (NMR) spectroscopy was employed to investigate intracellular pH differences in the anammox bacterium Kuenenia stuttgartiensis. With in vivo NMR, spectra were recorded of active, highly concentrated suspensions of K. stuttgartiensis in a wide-bore NMR tube. At different external pH values, two stable and distinct phosphate peaks were apparent in the recorded spectra. These peaks were equivalent with pH values of 7.3 and 6.3 and suggested the presence of a proton motive force over an intracytoplasmic membrane in K. stuttgartiensis. This study provides for the second time--after discovery of acidocalcisome-like compartments in Agrobacterium tumefaciens--evidence for an intracytoplasmic pH gradient in a chemotrophic prokaryotic cell.
Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
Wouter R L
WR
van der Star
Cor
C
Dijkema
Pieter
P
de Waard
Cristian
C
Picioreanu
Marc
M
Strous
Mark C M
MC
van Loosdrecht
D000693:Anaerobiosis; D001419:Bacteria / Q000166:cytology / Q000648:ultrastructure; D002451:Cell Compartmentation; D003593:Cytoplasm / Q000648:ultrastructure*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010084:Oxidation-Reduction; D010759:Phosphorus Isotopes / Q000378:metabolism*; D018892:Proton-Motive Force; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*
D010759:Phosphorus Isotopes; D000644:Quaternary Ammonium Compounds