Molecular weight and shape of the phycocyanin hexamer

✍ Scribed by Masanori Kato; Wylie I. Lee; B. E. Eichinger; J. M. Schurr

• Publisher: Wiley (John Wiley & Sons)
• Year: 1974
• Tongue: English
• Weight: 642 KB
• Volume: 13
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1974.360131111

✦ Synopsis

Abstract

The hexamer of phycocyanin from Phormidium luridum has been isolated and purified by ammonium sulfate fractionation and gel chromatography. The protein is characterized by the sedimentation constant S°~20, w~ = 10.2S, the diffusion coefficient D~20, w~ = 4.73 × 10^−7^ cm^2^/sec, and intrinsic viscosity [η] = 3.89 ml/g. The molecular weight of the aggregate is 209,000. The shape and dimensions of the hexamer are discussed in terms of a model consisting of subunits arranged with C~6~ symmetry. The monomers, assumed to be spherical, are found to have a radius of 22 Å, and the diameter across the hexamer is 132 Å. The latter figure agrees closely with dimensions observed in electron micrographs.