title: Spectroscopic investigation on the energy transfer process in photosynthetic apparatus of cyanobacteria.
abstract: In this work, we employ cyanobacteria, Spirulina platensis, and separate their photosynthetic apparatus, phycobilisome (PBS), thylakoid membrane and phycobilisome-thylakoid membrane complex. The steady state absorption spectra, fluorescence spectra and corresponding deconvoluted spectra and picosecond time-resolved spectra are used to investigate the energy transfer process in phycobilisome-thylakoid membrane complex. The results on steady state spectra show chlorophylls of the photosystem II are able to transfer excitation energy to phycobilisome with Chla molecules selectively excited. The decomposition of the steady state spectra further suggest the uphill energy transfer originate from chlorophylls of photosystem II to cores of phycobilisome, while rods and cores of phycobilisome cannot receive energy from the chlorophylls of photosystem I. The time constant for the back energy transfer process is 18 ps.
authors.affiliation: The Center for Molecular Science, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100080, China. liye188@hotmail.com
authors.forename: Ye
authors.initials: Y
authors.lastname: Li
authors.forename: Bei
authors.initials: B
authors.lastname: Wang
authors.forename: Xi-Cheng
authors.initials: XC
authors.lastname: Ai
authors.forename: Xing-Kang
authors.initials: XK
authors.lastname: Zhang
authors.forename: Jing-Quan
authors.initials: JQ
authors.lastname: Zhao
authors.forename: Li-Jin
authors.initials: LJ
authors.lastname: Jiang
mesh_terms: D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism; D000458:Cyanobacteria / Q000378:metabolism*; D004735:Energy Transfer; D045331:Photosystem I Protein Complex / Q000737:chemistry / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000378:metabolism*; D045524:Phycobilisomes / Q000737:chemistry / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D020524:Thylakoids / Q000737:chemistry / Q000378:metabolism
chemical_list: D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D045524:Phycobilisomes; D002734:Chlorophyll