5TJF

The crystal structure of Allophycocyanin from the red algae Gracilaria chilensis

Summary for 5TJF

• Entry DOI: 10.2210/pdb5tjf/pdb
• Descriptor: Allophycocyanin alpha subunit, Allophycocyanin beta subunit, PHYCOCYANOBILIN, ... (7 entities in total)
• Functional Keywords: allophycocianin, phycobilisome, phycobiliproteins, fret, photosynthesis
• Biological source: Gracilaria chilensis (Red alga); More
• Cellular location: Plastid, chloroplast thylakoid membrane ; Peripheral membrane protein ; Stromal side : A0A141SEH2 A0A141SEH3
• Total number of polymer chains: 2
• Total formula weight: 37075.55

Authors

Figueroa, M.,Dagnino, J.,Kerff, F.,Chartier, P.,Bunster, M.,Martinez-Oyanedel, J. (deposition date: 2016-10-04, release date: 2017-05-24, Last modification date: 2025-04-02)

Primary citation

Dagnino-Leone, J.,Figueroa, M.,Mella, C.,Vorphal, M.A.,Kerff, F.,Vasquez, A.J.,Bunster, M.,Martinez-Oyanedel, J.
Structural models of the different trimers present in the core of phycobilisomes from Gracilaria chilensis based on crystal structures and sequences.
PLoS ONE, 12:e0177540-e0177540, 2017

PubMed Abstract: Phycobilisomes (PBS) are accessory light harvesting protein complexes that directionally transfer energy towards photosystems. Phycobilisomes are organized in a central core and rods radiating from it. Components of phycobilisomes in Gracilaria chilensis (Gch) are Phycobiliproteins (PBPs), Phycoerythrin (PE), and Phycocyanin (PC) in the rods, while Allophycocyanin (APC) is found in the core, and linker proteins (L). The function of such complexes depends on the structure of each component and their interaction. The core of PBS from cyanobacteria is mainly composed by cylinders of trimers of α and β subunits forming heterodimers of Allophycocyanin, and other components of the core including subunits αII and β18. As for the linkers, Linker core (LC) and Linker core membrane (LCM) are essential for the final emission towards photoreaction centers. Since we have previously focused our studies on the rods of the PBS, in the present article we investigated the components of the core in the phycobilisome from the eukaryotic algae, Gracilaria chilensis and their organization into trimers. Transmission electron microscopy provided the information for a three cylinders core, while the three dimensional structure of Allophycocyanin purified from Gch was determined by X-ray diffraction method and the biological unit was determined as a trimer by size exclusion chromatography. The protein sequences of all the components of the core were obtained by sequencing the corresponding genes and their expression confirmed by transcriptomic analysis. These subunits have seldom been reported in red algae, but not in Gracilaria chilensis. The subunits not present in the crystallographic structure were modeled to build the different composition of trimers. This article proposes structural models for the different types of trimers present in the core of phycobilisomes of Gch as a first step towards the final model for energy transfer in this system.

PubMed: 28542288
DOI: 10.1371/journal.pone.0177540

Experimental method

X-RAY DIFFRACTION (2.3 Å)