title: Spectral heterogeneity in single light-harvesting chlorosomes from green sulfur photosynthetic bacterium chlorobium tepidum.
abstract: The fluorescence emission properties of single chlorosomes from the green sulfur photosynthetic bacterium Chlorobium (Chl.) tepidum are studied for the first time, using a total internal reflection fluorescence microscope. The fluorescence peak positions of bacteriochlorophyll (BChl)-c self-aggregates in a single chlorosome of Chl. tepidum were widely distributed in the wavelength region between 750 and 768 nm, and the standard deviation (s.d. = 4.1 nm, n = 51) was larger than that of single chlorosomes of Chloroflexus (Cfl.) (s.d. = 1.9 nm, n = 50). The spectral heterogeneity among single chlorosomes from Chl. tepidum was in sharp contrast to those from Cfl. aurantiacus. The difference of chlorosomal spectral properties between Chl. tepidum and Cfl. aurantiacus at the single-unit level would be ascribed to the homolog composition of BChl-c--chlorosomes of Chl. tepidum have BChl substituted with various alkyl groups at both the 8- and 12-positions, whereas light-harvesting BChl-c molecules in Cfl. chlorosomes have the same substituents at the 8- (ethyl group) and 12- (methyl group) positions.
authors: Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, Japan.
authors: Yoshitaka
authors: Y
authors: Saga
authors: Tetsuichi
authors: T
authors: Wazawa
authors: Tadashi
authors: T
authors: Mizoguchi
authors: Yoshiharu
authors: Y
authors: Ishii
authors: Toshio
authors: T
authors: Yanagida
authors: Hitoshi
authors: H
authors: Tamiaki
mesh_terms: D019414:Chlorobi / Q000737:chemistry*; D008027:Light; D008856:Microscopy, Fluorescence / Q000379:methods*; D015388:Organelles / Q000737:chemistry*; D013050:Spectrometry, Fluorescence