Transmission electron microscopic study on supramolecular nanostructures of bacteriochlorophyll self-aggregates in chlorosomes of green photosynthetic bacteria.
Supramolecular nanostructures of bacteriochlorophyll (BChl) self-aggregates in major light-harvesting complexes (chlorosomes) of green photosynthetic bacteria were successfully observed by freeze-fracture transmission electron microscope. Rod-shaped nanostructures with approximately 10 nm in diameter could be visualized in three types of green sulfur bacteria (Chlorobium). Diameter of the rod-shaped nanostructures in Chlorobium chlorosomes was independent of the molecular structures of their light-harvesting pigments, namely BChl-c or d. In contrast, chlorosomes of the green filamentous bacterium Chloroflexus aurantiacus had rod-shaped nanostructures with approximately 5 nm in diameter. The present results support that BChl self-aggregates in chlorosomes form rod-shaped nanostructures called rod-elements with approximately 10- and 5-nm diameters for Chlorobium and Chloroflexus, respectively.
Saga
Yoshitaka
Y
Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
Tamiaki
Hitoshi
H
D001419:Bacteria / Q000378:metabolism*; D020130:Bacterial Chromatophores / Q000737:chemistry*; D001429:Bacteriochlorophylls / Q000737:chemistry*; D005614:Freeze Fracturing; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D008956:Models, Chemical; D036103:Nanotechnology / Q000379:methods*; D010788:Photosynthesis
D001429:Bacteriochlorophylls; D045342:Light-Harvesting Protein Complexes