7EFW

Crystal structure of hexameric state of C-phycocyanin from Thermoleptolyngbya sp. O-77

Summary for 7EFW

• Entry DOI: 10.2210/pdb7efw/pdb
• Descriptor: C-phycocyanin alpha chain, C-phycocyanin beta chain, PHYCOCYANOBILIN, ... (5 entities in total)
• Functional Keywords: light-harvesting complex, photosynthesis
• Biological source: Leptolyngbya sp. O-77; More
• Total number of polymer chains: 12
• Total formula weight: 224820.75

Authors

Minato, T.,Teramoto, T.,Hung, N.K.,Yamada, K.,Ogo, S.,Kakuta, Y.,Yoon, K.S. (deposition date: 2021-03-23, release date: 2021-11-17, Last modification date: 2023-11-29)

Primary citation

Minato, T.,Teramoto, T.,Adachi, N.,Hung, N.K.,Yamada, K.,Kawasaki, M.,Akutsu, M.,Moriya, T.,Senda, T.,Ogo, S.,Kakuta, Y.,Yoon, K.S.
Non-conventional octameric structure of C-phycocyanin.
Commun Biol, 4:1238-1238, 2021

PubMed Abstract: C-phycocyanin (CPC), a blue pigment protein, is an indispensable component of giant phycobilisomes, which are light-harvesting antenna complexes in cyanobacteria that transfer energy efficiently to photosystems I and II. X-ray crystallographic and electron microscopy (EM) analyses have revealed the structure of CPC to be a closed toroidal hexamer by assembling two trimers. In this study, the structural characterization of non-conventional octameric CPC is reported for the first time. Analyses of the crystal and cryogenic EM structures of the native CPC from filamentous thermophilic cyanobacterium Thermoleptolyngbya sp. O-77 unexpectedly illustrated the coexistence of conventional hexamer and novel octamer. In addition, an unusual dimeric state, observed via analytical ultracentrifugation, was postulated to be a key intermediate structure in the assemble of the previously unobserved octamer. These observations provide new insights into the assembly processes of CPCs and the mechanism of energy transfer in the light-harvesting complexes.

PubMed: 34716405
DOI: 10.1038/s42003-021-02767-x

Experimental method

X-RAY DIFFRACTION (1.65 Å)