Four distinct trimeric forms of light-harvesting complex II isolated from the green alga Chlamydomonas reinhardtii
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Light-harvesting complex II (LHCII) absorbs light energy and transfers it primarily to photosystem II in green algae and land plants. Although the trimeric structure of LHCII is conserved between the two lineages, its subunit composition and function are believed to differ significantly. In this study, we purified four LHCII trimers from the green alga Chlamydomonas reinhardtii and analyzed their biochemical properties. We used several preparation methods to obtain four distinct fractions (fractions 1–4), each of which contained an LHCII trimer with different contents of Type I, III, and IV proteins. The pigment compositions of the LHCIIs in the four fractions were similar. The absorption and fluorescence spectra were also similar, although the peak positions differed slightly. These results indicate that this green alga contains four types of LHCII trimer with different biochemical and spectroscopic features. Based on these findings, we discuss the function and structural organization of green algal LHCII antennae.
KeywordsChlamydomonas Light-harvesting complex II trimer Photosystem II Subunit composition
Coomassie brilliant blue
Light-harvesting complex II
2-(N-morpholino) ethanesulfonic acid
Sucrose density gradient
Sodium dodecyl sulfate–polyacrylamide gel electrophoresis
Ultra-performance liquid chromatography
We thank Ms. Rie Uno (Osaka City University), Mr. Daisuke Namba (Osaka City University), and Ms. Chiyo Noda (National Institute for Basic Biology) for their assistance with purification and analysis. We are also grateful to Prof. Nobuo Kamiya (Osaka City University) and Associate Prof. Ikuko Miyahara (Osaka City University) for providing laboratory access. This work was funded by the Joint Usage/Research Program of the Artificial Photosynthesis, Osaka City University. K.K. and J.M. are grateful for the continued support of JST CREST, Japan (Grant No. JPMJCR13M4).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Ikeuchi M, Inoue Y (1988) A new 4.8-kDa polypeptide intrinsic to the PS II reaction center, as revealed by modified SDS-PAGE with improved resolution of low-molecular-weight proteins. Plant Cell Physiol 29:1233–1239Google Scholar