Fusion of chromatophores from photosynthetic bacteria with a supported lipid layer: characterization of the electric units.
Direct electrometric measurements of membrane potential changes are a valuable tool for study of vectorial transfer of electrons, protons, and ions. Commonly model membrane systems are created by fusion of lipid/protein vesicles with lipid-coated thin films. We characterized the electric units resulting from this process using chromatophores from the purple bacterium Rhodobacter sphaeroides and either a Mylar film or a planar modified gold electrode as support. Investigation of the shunting activity of the ionophore gramicidin on the flash-induced potential change demonstrates fusion of individual chromatophores to form independent 'blisters', which preserve an interior aqueous compartment. Under current-clamp conditions the photovoltage follows the change of the membrane potential of the individual blisters.
Keller
S
S
Section de Bioénergétique, CEA Saclay, France.
Riou
Y
Y
Laval
J
J
Leibl
W
W
D020130:Bacterial Chromatophores / Q000502:physiology* / Q000648:ultrastructure; D004594:Electrophysiology / Q000379:methods; D007425:Intracellular Membranes / Q000502:physiology; D008027:Light; D008561:Membrane Fusion; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques / Q000295:instrumentation; D010788:Photosynthesis; D012242:Rhodobacter sphaeroides / Q000502:physiology*