Protein structural deformation induced lifetime shortening of photosynthetic bacteria light-harvesting complex LH2 excited state.
Photosynthetic bacterial light-harvesting antenna complex LH2 was immobilized on the surface of TiO(2) nanoparticles in the colloidal solution. The LH2/TiO(2) assembly was investigated by the time-resolved spectroscopic methods. The excited-state lifetimes for carotenoid-containing and carotenoidless LH2 have been measured, showing a decrease in the excited-state lifetime of B850 when LH2 was immobilized on TiO(2). The possibility that the decrease of the LH2 excited-state lifetime being caused by an interfacial electron transfer reaction between B850 and the TiO(2) nanoparticle was precluded experimentally. We proposed that the observed change in the photophysical properties of LH2 when assembled onto TiO(2) nanoparticles is arising from the interfacial-interaction-induced structural deformation of the LH2 complex deviating from an ellipse of less eccentric to a more eccentric ellipse, and the observed phenomenon can be accounted by an elliptical exciton model. Experiment by using photoinactive SiO(2) nanoparticle in place of TiO(2) and core complex LH1 instead of LH2 provide further evidence to the proposed mechanism.
Chen
Xing-Hai
XH
Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing.
Zhang
Lei
L
Weng
Yu-Xiang
YX
Du
Lu-Chao
LC
Ye
Man-Ping
MP
Yang
Guo-Zhen
GZ
Fujii
Ritsuko
R
Rondonuwu
Ferdy S
FS
Koyama
Yasushi
Y
Wu
Yi-Shi
YS
Zhang
J P
JP
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D055592:Biophysical Phenomena; D001703:Biophysics; D003102:Colloids; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D046912:Multiprotein Complexes; D009154:Mutation; D049329:Nanostructures; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000235:genetics; D012242:Rhodobacter sphaeroides / Q000737:chemistry / Q000235:genetics; D013053:Spectrophotometry; D014025:Titanium
D001426:Bacterial Proteins; D003102:Colloids; D045342:Light-Harvesting Protein Complexes; D046912:Multiprotein Complexes; D045332:Photosystem II Protein Complex; C009495:titanium dioxide; D014025:Titanium