1KN1

Crystal structure of allophycocyanin

Summary for 1KN1

• Entry DOI: 10.2210/pdb1kn1/pdb
• Descriptor: Allophycocyanin, PHYCOCYANOBILIN, ... (4 entities in total)
• Functional Keywords: helix-turn-helix, electron transport
• Biological source: Porphyra yezoensis; More
• Total number of polymer chains: 2
• Total formula weight: 36020.98

Authors

Liang, D.C.,Liu, J.Y.,Jiang, T.,Zhang, J.P.,Chang, W.R. (deposition date: 2001-12-18, release date: 2002-12-18, Last modification date: 2024-10-23)

Primary citation

Liu, J.Y.,Jiang, T.,Zhang, J.P.,Liang, D.C.
Crystal structure of Allophycocyanin from red algae Porphyra yezoensis at 2.2 A resolution
J.BIOL.CHEM., 274:16945-16952, 1999

PubMed Abstract: The crystal structure of allophycocyanin from red algae Porphyra yezoensis (APC-PY) at 2.2-A resolution has been determined by the molecular replacement method. The crystal belongs to space group R32 with cell parameters a = b = 105.3 A, c = 189.4 A, alpha = beta = 90 degrees, gamma = 120 degrees. After several cycles of refinement using program X-PLOR and model building based on the electron density map, the crystallographic R-factor converged to 19.3% (R-free factor is 26.9%) in the range of 10.0 to 2.2 A. The r.m.s. deviations of bond length and angles are 0.015 A and 2.9 degrees, respectively. In the crystal, two APC-PY trimers associate face to face into a hexamer. The assembly of two trimers within the hexamer is similar to that of C-phycocyanin (C-PC) and R-phycoerythrin (R-PE) hexamers, but the assembly tightness of the two trimers to the hexamer is not so high as that in C-PC and R-PE hexamers. The chromophore-protein interactions and possible pathway of energy transfer were discussed. Phycocyanobilin 1alpha84 of APC-PY forms 5 hydrogen bonds with 3 residues in subunit 2beta of another monomer. In R-PE and C-PC, chromophore 1alpha84 only forms 1 hydrogen bond with 2beta77 residue in subunit 2beta. This result may support and explain great spectrum difference exists between APC trimer and monomer.

PubMed: 10358042
DOI: 10.1074/jbc.274.24.16945

Experimental method

X-RAY DIFFRACTION (2.2 Å)