Watching the components of photosynthetic bacterial membranes and their in situ organisation by atomic force microscopy.
The atomic force microscope has developed into a powerful tool in structural biology allowing information to be acquired at submolecular resolution on the protruding structures of membrane proteins. It is now a complementary technique to X-ray crystallography and electron microscopy for structure determination of individual membrane proteins after extraction, purification and reconstitution into lipid bilayers. Moving on from the structures of individual components of biological membranes, atomic force microscopy has recently been demonstrated to be a unique tool to identify in situ the individual components of multi-protein assemblies and to study the supramolecular architecture of these components allowing the efficient performance of a complex biological function. Here, recent atomic force microscopy studies of native membranes of different photosynthetic bacteria with different polypeptide contents are reviewed. Technology, advantages, feasibilities, restrictions and limits of atomic force microscopy for the acquisition of highly resolved images of up to 10 A lateral resolution under native conditions are discussed. From a biological point of view, the new insights contributed by the images are analysed and discussed in the context of the strongly debated organisation of the interconnected network of membrane-associated chlorophyll-protein complexes composing the photosynthetic apparatus in different species of purple bacteria.
Scheuring
Simon
S
Institut Curie, UMR-CNRS 168 and LRC-CEA 34V, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France.
Lévy
Daniel
D
Rigaud
Jean-Louis
JL
D001419:Bacteria / Q000378:metabolism / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000378:metabolism; D002734:Chlorophyll / Q000737:chemistry; D018360:Crystallography, X-Ray; D014450:Electron Transport Complex III / Q000378:metabolism; D004583:Electrons; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry; D008566:Membranes / Q000378:metabolism* / Q000648:ultrastructure; D018625:Microscopy, Atomic Force / Q000379:methods*; D008854:Microscopy, Electron; D008954:Models, Biological; D010455:Peptides / Q000737:chemistry; D010788:Photosynthesis; D020560:Proteobacteria / Q000378:metabolism; D016992:Rhodobacter / Q000378:metabolism; D012242:Rhodobacter sphaeroides / Q000378:metabolism; D012246:Rhodospirillum / Q000378:metabolism
D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D008051:Lipid Bilayers; D010455:Peptides; C094744:light-harvesting complex 1, Rhodospirillum; D002734:Chlorophyll; D014450:Electron Transport Complex III