Conformational changes in photosynthetic pigment proteins on thylakoid membranes can lead to fast non-photochemical quenching in cyanobacteria  

作　　者：WANG ZhiCong DONG Jing LI DunHai 

机构地区：[1]Institute of Hydrobiology,Chinese Academy of Sciences,Wuhan 430072,China [2]Graduate University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China(Life Sciences)》2012年第8期726-734,共9页中国科学（生命科学英文版）

基　　金：supported by the National Basic Research Program of China(Grant No. 2008CB418002);the National Major Programs of Water Body Pollution Control and Remediation (Grant Nos. 2009ZX07104-005 and 2009ZX07106-001)

摘　　要：A high non-photochemical quenching(NPQ) appeared below the phase transition temperature when Microcystis aeruginosa PCC7806 cells were exposed to saturated light for a short time.This suggested that a component of NPQ,independent from state transition or photo-inhibition,had been generated in the PSII complex;this was a fast component responding to high intensity light.Glutaraldehyde(GA),commonly used to stabilize membrane protein conformations,resulted in more energy transfer to PSII reaction centers,affecting the energy absorption and dissipation process rather than the transfer process of phycobilisome(PBS).In comparison experiments with and without GA,the rapid light curves(RLCs) and fluorescence induction dynamics of the fast phase showed that excess excitation energy was dissipated by conformational change in the photosynthetic pigment proteins on the thylakoid membrane(PPPTM).Based on deconvolution of NPQ relaxation kinetics,we concluded that the fast quenching component(NPQ f) was closely related to PPPTM conformational change,as it accounted for as much as 39.42% of the total NPQ.We hypothesize therefore,that NPQ f induced by PPPTM conformation is an important adaptation mechanism for Microcystis blooms under high-intensity light during summer and autumn.A high non-photochemical quenching（NPQ） appeared below the phase transition temperature when Microcystis aeruginosa PCC7806 cells were exposed to saturated light for a short time.This suggested that a component of NPQ,independent from state transition or photo-inhibition,had been generated in the PSII complex;this was a fast component responding to high intensity light.Glutaraldehyde（GA）,commonly used to stabilize membrane protein conformations,resulted in more energy transfer to PSII reaction centers,affecting the energy absorption and dissipation process rather than the transfer process of phycobilisome（PBS）.In comparison experiments with and without GA,the rapid light curves（RLCs） and fluorescence induction dynamics of the fast phase showed that excess excitation energy was dissipated by conformational change in the photosynthetic pigment proteins on the thylakoid membrane（PPPTM）.Based on deconvolution of NPQ relaxation kinetics,we concluded that the fast quenching component（NPQ f） was closely related to PPPTM conformational change,as it accounted for as much as 39.42% of the total NPQ.We hypothesize therefore,that NPQ f induced by PPPTM conformation is an important adaptation mechanism for Microcystis blooms under high-intensity light during summer and autumn.

关 键 词：chlorophyll fluorescence PHOTOPROTECTION Microcystis aeruginosa non-photochemical quenching thylakoid membrane proteins 

分 类 号：Q51[生物学—生物化学] S512.101[农业科学—作物学]