9V7I

Phycobilisome rod R3 from Gloeobacter violaceus PCC 7421

Summary for 9V7I

• Entry DOI: 10.2210/pdb9v7i/pdb
• EMDB information: 64814
• Descriptor: Phycobilisome rod linker polypeptide CpcC1, Phycocyanin beta chain, Phycocyanin alpha chain, ... (6 entities in total)
• Functional Keywords: phycobilisome, photosynthesis
• Biological source: Gloeobacter violaceus PCC 7421; More
• Total number of polymer chains: 27
• Total formula weight: 609225.13

Authors

Burtseva, A.D.,Baymukhametov, T.N.,Slonimskiy, Y.B.,Popov, V.O.,Sluchanko, N.N.,Boyko, K.M. (deposition date: 2025-05-28, release date: 2025-09-24, Last modification date: 2025-10-29)

Primary citation

Burtseva, A.D.,Slonimskiy, Y.B.,Baymukhametov, T.N.,Sinetova, M.A.,Gvozdev, D.A.,Tsoraev, G.V.,Cherepanov, D.A.,Maksimov, E.G.,Popov, V.O.,Boyko, K.M.,Sluchanko, N.N.
Structure and quenching of a bundle-shaped phycobilisome.
Sci Adv, 11:eadz6774-eadz6774, 2025

PubMed Abstract: Cyanobacteria use soluble antenna megacomplexes, phycobilisomes (PBSs), to maximize light-harvesting efficiency and small photoswitchable orange carotenoid proteins (OCPs) to down-regulate PBSs in high light. Among known PBS morphologies, the one from the basal cyanobacterial genus still lacks detailed structural characterization. Here, we reconstructed a cryo-electron microscopy structure of the >10-megadalton PBS, with diverging, conformationally mobile bundles of rods composed of stacked phycoerythrin and phycocyanin hexamers, stemming from a pentacylindrical allophycocyanin core belted by auxiliary phycocyanin hexamers. We show how two -specific multidomain linker proteins, Glr1262 and Glr2806, maintain this bundle-shaped architecture and reveal its differential regulation via nonphotochemical quenching by two OCP types of that recognize separate binding sites within the allophycocyanin core, including lateral cylinders absent in tricylindrical cores.

PubMed: 41091862
DOI: 10.1126/sciadv.adz6774

Experimental method

ELECTRON MICROSCOPY (3.03 Å)