National Institute for Basic Biology

Environmental Biology

DIVISION OF ENVIRONMENTAL PHOTOBIOLOGY

Professor

MINAGAWA, Jun

Associate Professor

YOKONO, Makio

Assistant Professor:
KIM, EunchulSpecially Appointed Assistant Professor:
KOSUGI, Makiko
Technical Staff:
NODA, Chiyo
Postdoctoral Fellow:
KAMADA, Konomi
ISHII, Asako
SOKENDAI Graduate Student: YANAKA, Ayako
Visiting Scientist:
DANN, Marcel
Technical Assistant:
YONEZAWA, Harumi
KADOWAKI, Tamaka
Admin Support Staff:
TOYAMA, Mami
SUZUKI, Yuka

I. Plant and Algal PSII–LHCII Supercomplexes:
Structure, Evolution and Energy Transfer.
Photosynthesis is the process conducted by plants and algae
to capture photons and store their energy in chemical forms.
The light-harvesting, excitation transfer, charge separation and electron transfer in photosystem II (PSII) are thecritical initial reactions of photosynthesis and thereby largely
determine its overall efficiency. Knowledge about the architectures and assemblies of plant and green algal PSII–lightharvesting complex II (LHCII) supercomplexes are rapidly
accumulating (Figure 1). We made pair-wise comparative
analyses between the supercomplexes from plants and green
algae to gain insights about the evolution of the PSII–LHCII
supercomplexes involving the peripheral small PSII subunits
that might have been acquired during the evolution (FigurePlants and algae have versatile abilities to acclimate themselves to changing environments. We are interested in theseacclimation processes, and how they efficiently yet safely
harness sunlight for photosynthesis under fluctuating lightconditions. Using a model green alga, we are studying themolecular mechanisms underlying photoacclimation of photosynthetic machinery. We are also applying knowledgeobtained in the studies of this model green alga to various
photosynthetic organisms, including phytoplankton andvascular plants, to explore how environmentally important
photosynthetic organisms thrive in their ecological niche.

Visual overview of this lab’s work

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Figure 1. The overall architecture of PSII–LHCII supercomplexes fromC. reinhardtii and vascular plants (C2S2 from Spinacia oleracea, C2S2M2from pea). Sheng et al. (2021) Plant Cell Physiol., 62:1108-1120.

2) and about the energy transfer pathways that define theirlight-harvesting and photoprotective properties (Figure 3)(Sheng et al., Plant Cell Physiol., 62:1108-1120).

II. Structural basis of LhcbM5-mediated statetransitions in green algae.
In green algae and plants, state transitions serve as a short-termlight-acclimation process in the regulation of the light-harvesting capacity of photosystems I and II (PSI and PSII, respectively). During the process, a portion of light-harvesting complex II(LHCII) is phosphorylated, dissociated from PSII and binds
with PSI to form the supercomplex PSI–LHCI–LHCII. We
reported high-resolution structures of PSI–LHCI–LHCII
from Chlamydomonas reinhardtii, revealing the mechanism ofassembly between the PSI–LHCI complex and two phosphorylated LHCII trimers containing all four types of LhcbM protein(Figure 4). Two specific LhcbM isoforms, namely LhcbM1 andLhcbM5, directly interact with the PSI core through their phosphorylated amino terminal regions. Furthermore, biochemicaland functional studies on mutant strains lacking either LhcbM1or LhcbM5 indicate that only LhcbM5 is indispensable in supercomplex formation. The results unravel the specific interactions
and potential excitation energy transfer routes between green
algal PSI and two phosphorylated LHCIIs (Pan et al., Nat.
Plants, 7:1119-1131).

Figure 2. Superposition of green algal and plant PSII–LHCII supercomplexes and evolutionary insights from pea C2S2M2 and C. reinhardtii
C2S2M2L2 supercomplexes. Sheng et al. (2021) Plant Cell Physiol.,
62:1108-1120.

Figure 3. Förster resonance energy transfer (FRET) networks of green
algal and plant PSII-LHCII supercomplexes and major energy transferpathways. Sheng et al. (2021) Plant Cell Physiol., 62:1108-1120.

Figure 4. Surface representation of the CrPSI–LHCI–LHCII supercomplex from the pph1;pbcp mutant strain, with pThr residues from LhcbM1and LhcbM5 highlighted in red. b, Detailed interaction between theN-terminal region of LhcbM1 and PSI core subunits PsaH and PsaL. c,Sequence alignment of the interaction-related regions of LhcbM1, PsaLand PsaH from C. reinhardtii (Cr) with Lhcb2, PsaL and PsaH fromZm, respectively. Conserved and variant residues involved in intersubunit interactions are indicated by blue and red asterisks, respectively. d,
Structural comparison of N-terminal five residues (shown as sticks)of CrLhcbM1 (carbon atoms coloured green) and ZmLhcb2 (carbonatoms coloured white). The PSI core is shown in electrostatic surface
mode with red and blue representing acidic and basic regions, respectively. e, Detailed interactions between the N-terminal region of LhcbM5
and the PSI core subunit PsaH. Hydrogen bond interactions are shown asblack dashed lines. Pan et al. (2021) Nat. Plants, 7:1119-1131.

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National Institute for Basic Biology

Environmental Biology

Publication List:〔Original Papers〕

T., Takahashi, S., Yoshida, T., Shimamura, S., Takaki, Y.,• Maeda,Nagai, Y., Toyoda, A., Suzuki, Y., Arimoto, A., Ishii, H., Satoh, N.,

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•
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•

Nishiyama, T., Hasebe, M., Maruyama, T., Minagawa, J., Obokata, J.,
and Shigenobu, S. (2021). Chloroplast acquisition without the genetransfer in kleptoplastic sea slugs, Plakobranchus ocellatus. eLife 10,e60176. DOI: 10.7554/eLife.60176
Morishita, J., Tokutsu, R., Minagawa, J., Hisabori, T., and Wakabayashi,
K. (2021). Characterization of Chlamydomonas reinhardtii Mutants
That Exhibit Strong Positive Phototaxis. Plants 10, 1483. DOI: 10.3390/plants10071483
Pan, X., Tokutsu, R., Li, A., Takizawa, K., Song, C., Murata, K.,
Yamasaki, T., Liu, Z., Minagawa, J., and Li, M. (2021). Structural basisof LhcbM5-mediated state transitions in green algae. Nat. Plants 7,1119+. DOI: 10.1038/s41477-021-00960-8
Tanno, A., Tokutsu, R., Arakaki, Y., Ueki, N., Minagawa, J., Yoshimura,K., Hisabori, T., Nozaki, H., and Wakabayashi, K.-I. (2021). The
four-celled Volvocales green alga Tetrabaena socialis exhibits weak
photobehavior and high-photoprotection ability. PLoS One 16,
e0259138. DOI: 10.1371/journal.pone.0259138
Tokutsu, R., Fujimura-Kamada, K., Yamasaki, T., Okajima, K.,
and Minagawa, J. (2021). UV-A/B radiation rapidly activatesphotoprotective mechanisms in Chlamydomonas reinhardtii. Plant
Physiol. 185, 1894–1902. DOI: 10.1093/plphys/kiab004
Zhang, X.J., Fujita, Y., Tokutsu, R., Minagawa, J., Ye, S., and Shibata,Y. (2021). High-Speed Excitation-Spectral Microscopy Uncovers In
Situ Rearrangement of Light-Harvesting Apparatus in Chlamydomonas
during State Transitions at Submicron Precision. Plant Cell Physiol. 62,872–882. DOI: 10.1093/pcp/pcab047〔Review Article〕

M., Minagawa, J., and Takahashi, Y. (2021). Photosynthesis and• Hippler,
Chloroplast Regulation-Balancing Photosynthesis and Photoprotection•84

under Changing Environments. Plant Cell Physiol. 62, 1059–1062.
DOI: 10.1093/pcp/pcab139
Sheng, X., Liu, Z., Kim, E., Minagawa, J. (2021). Plant and algal PSIILHCII supercomplexes: structure, evolution and energy transfer. Plant
Cell Physiol 62: 1108-1120. DOI: 10.1093/pcp/pcab072