The structure at 2 Å resolution of Phycocyanin from Gracilaria chilensis and the energy transfer network in a PC-PC complex

Bruna, C; Almonacid D; Figueroa, M; Martinez-Oyanedel, J; Bunster, M; Contreras-Martel, C; Poo-Caamano, G; Matamala Á.

Keywords: sequence, dynamics, model, energy, acid, system, fluorescence, cyanobacteria, protein, conductance, structure, ray, resonance, light, interaction, drug, molecular, gracilaria, harvesting, rhodophyta, article, red, analysis, function, proteomics, chilensis, alga, phycocyanin, crystallography, cyanobacterium, c, mathematical, computing, amino, priority, nonhuman, journal, X, Transfer, unclassified, structural, chromatophore, phycobiliprotein


Phycocyanin is a phycobiliprotein involved in light harvesting and conduction of light to the reaction centers in cyanobacteria and red algae. The structure of C-phycocyanin from Gracilaria chilensis was solved by X-ray crystallography at 2.0 Å resolution in space group P2 1. An interaction model between two PC heterohexamers was built, followed by molecular dynamic refinement. The best model showed an inter-hexamer rotation of 23°. The coordinates of a PC heterohexamer (??) 6 and of the PC-PC complex were used to perform energy transfer calculations between chromophores pairs using the fluorescence resonance energy transfer approach (FRET). Two main intra PC ( I? 3 82 ? I? 1 84 ? I? 5 84 ? I? 6 82 and I? 3 153 ? I? 5 153) and two main inter PC ( I? 6 82 ? II? 3 82 and I? 5 153 ? II? 3 153) pathways were proposed based on the values of the energy transfer constants calculated for all the chromophore pairs in the hexamer and in the complex. © 2006 Elsevier B.V. All rights reserved.

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Volumen: 125
Número: 2-3
Fecha de publicación: 2007
Página de inicio: 388
Página final: 396