Archives of Microbiology

, Volume 110, Issue 1, pp 61–75

Characterization and structural properties of the major biliproteins of Anabaena sp.

  • Donald A. Bryant
  • Alexander N. Glazer
  • Frederick A. Eiserling
Article

DOI: 10.1007/BF00416970

Cite this article as:
Bryant, D.A., Glazer, A.N. & Eiserling, F.A. Arch. Microbiol. (1976) 110: 61. doi:10.1007/BF00416970

Abstract

Studies are presented of the biliproteins of Anabaena sp. This filamentous cyanobacterium contains three major biliproteins. Whereas two of these, C-phycocyanin and allophycocyanin, are common to all cyanobacteria, the third, phycoerythrocyanin (λmax∼568nm) has hitherto not been described and its distribution among cyanobacteria appears to be limited.

Anabaena variabilis and Anabaena sp. 6411 allophycocyanin, C-phycocyanin, and phycoerythrocyanin were purified to homogeneity and characterized with respect to molecular weight, isoelectric point, absorption spectrum and amino acid composition. The α and β subunits of each of these proteins were also purified to homogeneity and characterized in the same manner. The tetrapyrrole chromophore content was determined for each of the proteins and subunits. The α subunit of phycoerythrocyanin carries a novel phycobiliviolin-like chromophore. This chromophore has not previously been detected in cyanobacterial biliproteins, but has been noted as a prosthetic group of a cryptophytan phycocyanin.

Sedimentation equilibrium studies show that at pH 7.0, at protein concentrations of 0.2–0.6 mg/ml, allophycocyanin, C-phycocyanin and phycoerythrocyanin, each exists as a trimeric aggregate, (αβ)3, of molecular weight of approximately 105000. Structural studies of microcrystals of these three biliproteins by electron microscopy and X-ray diffraction reveal a common plan for the construction of higher assembly forms. The major building block appears to be the trimer (αβ)3. It is proposed that this is a dise-like structure about 3.0×12.0 nm. The individual α or β subunits are roughly spherical, 3 nm in diameter. Allophycocyanin trimers stack to form bundles of rods which form long needles. Both phycocyanin and phycoerythrocyanin form double dises (αβ)6 which are visible as ring-shaped structures by electron microscopy. The mode of assembly of the biliproteinstructures in the phycobilisome is, as yet, unknown.

Key words

BiliproteinsPhycoerythrocyaninAssembly formsAnabaena sp.Photosynthesis

Abbreviation Used

SDS

sodium dodecyl sulfate

Copyright information

© Springer-Verlag 1976

Authors and Affiliations

  • Donald A. Bryant
    • 1
    • 2
    • 3
  • Alexander N. Glazer
    • 1
    • 2
    • 3
  • Frederick A. Eiserling
    • 1
    • 2
    • 3
  1. 1.Department of Biological Chemistry (UCLA School of Medicine)University of CaliforniaLos AngelesUSA
  2. 2.Department of BacteriologyUniversity of CaliforniaLos AngelesUSA
  3. 3.the Molecular Biology InstituteUniversity of CaliforniaLos AngelesUSA