2J96

The E-configuration of alfa-Phycoerythrocyanin

Summary for 2J96

• Entry DOI: 10.2210/pdb2j96/pdb
• Related: 2C7J 2C7K 2C7L
• Descriptor: PHYCOERYTHROCYANIN ALPHA CHAIN, PHYCOVIOLOBILIN (3 entities in total)
• Functional Keywords: electron transport, z- to e-isomerization, transport, chromophore, bile pigment, phycobilisome, photosynthesis, light harvesting, phycobiliproteins
• Biological source: MASTIGOCLADUS LAMINOSUS
• Total number of polymer chains: 2
• Total formula weight: 36340.76

Authors

Schmidt, M.,Patel, A.,Zhao, Y.,Reuter, W. (deposition date: 2006-11-02, release date: 2007-01-23, Last modification date: 2024-11-20)

Primary citation

Schmidt, M.,Patel, A.,Zhao, Y.,Reuter, W.
Structural Basis for the Photochemistry of Alfa-Phycoerythrocyanin
Biochemistry, 46:416-, 2007

PubMed Abstract: Phycobiliproteins and phytochromes are light-harvesting and light-sensing proteins containing linear tetrapyrroles, so-called bile chromophores. The chromophores in certain biliproteins, including the phytochromes, isomerize reversibly from a stable Z-configuration to a stable E-configuration when irradiated with light of the appropriate wavelength. Here, we report the crystal structure of alpha-phycoerythrocyanin with its chromophore in the E-configuration, compare it with the Z-configuration found in trimeric phycoerythrocyanin, and reveal the structural bases of the isomerization. The geometric changes of the chromophore account for the large spectral shift, which characterizes the overall transition. Interactions of the chromophore A and D pyrrole rings with flexible protein moieties are required for the formation and stabilization of the isomers. We predict that the results will hold for all photoactive biliproteins.

PubMed: 17209552
DOI: 10.1021/BI061844J

Experimental method

X-RAY DIFFRACTION (2.25 Å)