A groundbreaking study has unveiled a unique light-harvesting structure in marine algae that could accelerate the development of artificial photosynthesis systems, potentially transforming solar energy into sustainable fuels like hydrogen.
🌊 Marine Algae Photosynthesis: Nature’s Efficient Energy Blueprint
Photosynthesis—the natural process that converts sunlight into chemical energy and releases oxygen—is the foundation of life on Earth. Scientists have long aimed to replicate this process through artificial photosynthesis to create renewable energy solutions.
A recent study led by Dr. Romain La Rocca, Dr. Fusamichi Akita, and Dr. Jian-Ren Shen from Okayama University, Japan, offers new insights into the photosynthetic machinery of Chrysotila roscoffensis, a marine alga belonging to the coccolithophore group. These algae are crucial to marine ecosystems, known for their role in carbon fixation and oceanic calcium carbonate production.
Published in Nature Communications on May 5, 2025, the research unveils the detailed structure of a previously unexplored photosystem II (PSII)–FCPII supercomplex in this marine alga.
🔬 Key Discovery: Unique PSII–FCPII Complex in Haptophytes
Using high-resolution cryo-electron microscopy (cryo-EM) at 2.2 Å resolution, the research team created the first structural model of the PSII-FCPII complex in haptophytes—a major class of marine algae.
Unlike PSII structures in diatoms and green algae, this haptophyte complex displays a distinct antenna protein arrangement. Each PSII monomer is surrounded by six FCPII (fucoxanthin chlorophyll a/c-binding protein) units, optimized for efficient light capture and energy transfer.
“This unique antenna configuration shows how marine algae have adapted their photosynthetic systems to thrive under specific light conditions in ocean environments,” explains Dr. La Rocca.
⚡ FCPII-2: The Central Player in Light-Harvesting
Among the antenna proteins, FCPII-2 emerged as a central hub. This protein efficiently gathers energy from surrounding FCPIIs and delivers it to the PSII core subunit CP47. Notably, FCPII-2 is rich in fucoxanthin pigments, which absorb a broader light spectrum and prevent photodamage by dissipating excess energy.
These pigments contribute to the algae’s superior ability to harvest light under low-light and variable oceanic conditions—making them ideal models for bio-inspired solar energy technologies.
🧬 Identification of a New PSII Subunit: Psb36
The researchers also sequenced Psb36, a previously uncharacterized protein found at the interface between the PSII core and its antenna system. Although similar structures had been observed in red algae and diatoms, this is the first time the sequence of Psb36 has been identified and analyzed in detail.
🌍 Why This Matters: Toward Next-Generation Artificial Photosynthesis
Marine algae like Chrysotila roscoffensis contribute up to 50% of ocean biomass and play a key role in the global carbon cycle. By uncovering the secrets of their light-harvesting systems, scientists can develop more efficient, nature-inspired artificial photosynthetic systems.
“Understanding the structure of these efficient photosystems brings us closer to harnessing solar energy the way nature does,” says Dr. Jian-Ren Shen.
This discovery may guide the creation of next-gen solar energy technologies, including artificial leaves, solar-to-fuel systems, and photobioreactors, that mimic the structure and function of algae-based photosynthesis.
📚 Reference
Romain La Rocca et al., Structure of a photosystem II–FCPII supercomplex from a haptophyte reveals a distinct antenna organization, Nature Communications (2025).
DOI: 10.1038/s41467-025-59512-9