Characterization of photosystem I complexes from Acaryochloris with low-energy Chlorophyll d

July 4, 2024

Researchers from Shizuoka University along with Okayama University and the RIKEN CSRS purified photosystem I (PSI) trimer and monomer cores from cyanobacteria Acaryochloris sp. NBRC 102871 (NBRC102871) with low-energy Chlorophyll d and characterized those molecules.

In ultraviolet-visible and fluorescent spectroscopies, low-energy chlorophylls d were observed from the PSI monomer and trimer core. The characteristics of those spectra were found to be significantly different. This suggests that the structure changes around the chlorophylls d due to the interaction between PSI monomers induced the formation of different low-energy chlorophylls d in the PSI trimer and monomer. This is characteristic of Acaryochloris species, which have various low-energy chlorophylls d. Chlorophylls d are present only in Acaryochloris species, but not in oxygenic phototrophs such as other cyanobacteria, algae, or land plants. The research group analyzed PSI in Acaryochloris marina MBIC 11017 in 2023. However, they did not observe chlorophylls d with as low energy as NBRC102871’s. This research revealed that a variety of low-energy chlorophylls d bind to PSI in Acaryochloris species, which is a unique organism group.

The results of this study could be essential to understand the evolution of Acaryochloris species.

Original article

Photosynthesis Research doi: 10.1007/s11120-024-01108-3

R. Nagao, H. Yamamoto, H. Ogawa, H. Ito, Y. Yamamoto, T. Suzuki, K. Kato, Y. Nakajima, N. Dohmae, J.-R. Shen,

"Presence of low-energy chlorophylls d in photosystem I trimer and monomer cores isolated from Acaryochloris sp. NBRC 102871".

Contact

Naoshi Dohmae
Unit Leader
Biomolecular Characterization Unit