title: Direct energy transfer from the major antenna to the photosystem II core complexes in the absence of minor antennae in liposomes.
abstract: Minor antennae of photosystem (PS) II, located between the PSII core complex and the major antenna (LHCII), are important components for the structural and functional integrity of PSII supercomplexes. In order to study the functional significance of minor antennae in the energetic coupling between LHCII and the PSII core, characteristics of PSII-LHCII proteoliposomes, with or without minor antennae, were investigated. Two types of PSII preparations containing different antenna compositions were isolated from pea: 1) the PSII preparation composed of the PSII core complex, all of the minor antennae, and a small amount of major antennae (MCC); and 2) the purified PSII dimeric core complexes without periphery antenna (CC). They were incorporated, together with LHCII, into liposomes composed of thylakoid membrane lipids. The spectroscopic and functional characteristics were measured. 77K fluorescence emission spectra revealed an increased spectral weight of fluorescence from PSII reaction center in the CC-LHCII proteoliposomes, implying energetic coupling between LHCII and CC in the proteoliposomes lacking minor antennae. This result was further confirmed by chlorophyll a fluorescence induction kinetics. The incorporation of LHCII together with CC markedly increased the antenna cross-section of the PSII core complex. The 2,6-dichlorophenolindophenol photoreduction measurement implied that the lack of minor antennae in PSII supercomplexes did not block the energy transfer from LHCII to the PSII core complex. In conclusion, it is possible, in liposomes, that LHCII transfer energy directly to the PSII core complex, in the absence of minor antennae.
authors.affiliation: Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Beijing 100093, China; University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China.
authors.forename: Ruixue
authors.initials: R
authors.lastname: Sun
authors.affiliation: Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Beijing 100093, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.affiliation: Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Beijing 100093, China; University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China.
authors.forename: Lianqing
authors.initials: L
authors.lastname: Dong
authors.affiliation: Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Beijing 100093, China; University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Institut für Allgemeine Botanik, Johannes-Gutenberg-Universität Mainz, Johannes-von-Müllerweg 6, 55099 Mainz, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Paulsen
authors.affiliation: Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Beijing 100093, China. Electronic address: yangch@ibcas.ac.cn.
authors.forename: Chunhong
authors.initials: C
authors.lastname: Yang
mesh_terms: D004735:Energy Transfer; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D010777:Photochemistry; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D045342:Light-Harvesting Protein Complexes; D008081:Liposomes; D045332:Photosystem II Protein Complex
keywords: Light-harvesting complex; Minor antenna; Photosystem II; Protein–protein interaction; Proteoliposome