Extended Data Fig. 4: Assembly of the PBS.
From: Structures of a phycobilisome in light-harvesting and photoprotected states
The core cylinders consist of four stacked discs; each disc contains three α- and three β-type Apc proteins that form the signature (αβ)6 hexamers. Besides the canonical ApcA and ApcB proteins, B1 and B2 cylinders contain one copy each of ApcD and ApcF, as well as the phycobiliprotein domain of ApcE. These are symmetrically arranged in the two bottom cylinders, oriented towards the membrane. ApcG, ApcD and ApcE protrude out of the core, indicating their likely role in contacting the photosystems. Each rod contains three stacked discs, each consisting of one CpcA/B hexamer. The overall architecture of the PBS core is in agreement with modelling predictions43.
