title: Harvesting Far-Red Light by Chlorophyll f in Photosystems I and II of Unicellular Cyanobacterium strain KC1.
abstract: Cells of a unicellular cyanobacterium strain KC1, which were collected from Japanese fresh water Lake Biwa, formed chlorophyll (Chl) f at 6.7%, Chl a' at 2.0% and pheophytin a at 0.96% with respect to Chl a after growth under 740 nm light. The far-red-acclimated cells (Fr cells) formed extra absorption bands of Chl f at 715 nm in addition to the major Chl a band. Fluorescence lifetimes were measured. The 405-nm laser flash, which excites mainly Chl a in photosystem I (PSI), induced a fast energy transfer to multiple fluorescence bands at 720-760 and 805 nm of Chl f at 77 K in Fr cells with almost no PSI-red-Chl a band. The 630-nm laser flash, which mainly excited photosystem II (PSII) through phycocyanin, revealed fast energy transfer to another set of Chl f bands at 720-770 and 810 nm as well as to the 694-nm Chl a fluorescence band. The 694-nm band did not transfer excitation energy to Chl f. Therefore, Chl a in PSI, and phycocyanin in PSII of Fr cells transferred excitation energy to different sets of Chl f molecules. Multiple Chl f forms, thus, seem to work as the far-red antenna both in PSI and PSII. A variety of cyanobacterial species, phylogenically distant from each other, seems to use a Chl f antenna in far-red environments, such as under dense biomats, in colonies, or under far-red LED light.
authors: Center for Gene Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan itoh2nd@gmail.com.
authors: Shigeru
authors: S
authors: Itoh
authors: Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
authors: Tomoki
authors: T
authors: Ohno
authors: Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya 466-8555, Japan.
authors: Tomoyasu
authors: T
authors: Noji
authors: Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan.
authors: Hisanori
authors: H
authors: Yamakawa
authors: Division of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.
authors: Hirohisa
authors: H
authors: Komatsu
authors: Division of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.
authors: Katsuhiro
authors: K
authors: Wada
authors: Division of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.
authors: Masami
authors: M
authors: Kobayashi
authors: Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan Graduate School of Global and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
authors: Hideaki
authors: H
authors: Miyashita
mesh_terms: D002734:Chlorophyll / Q000031:analogs & derivatives* / Q000378:metabolism; D000458:Cyanobacteria / Q000378:metabolism*; D045331:Photosystem I Protein Complex / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*
chemical_list: D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; C583352:chlorophyll f; D002734:Chlorophyll
keywords: Chlorophyll f; Cyanobacteria; Far-red light; Light harvesting; PSI; PSII