, Volume 183, Issue 1, pp 120–125

Localization of a multifunctional chaperonin (GroEL protein) in nitrogen-fixing Anabaena PCC 7120

Presence in vegetative cells and heterocysts
  • Karin M. Jāger
  • Birgitta Bergman

DOI: 10.1007/BF00197575

Cite this article as:
Jāger, K.M. & Bergman, B. Planta (1991) 183: 120. doi:10.1007/BF00197575


The occurrence and distribution of a multifunctional chaperonin-60 (cpn60), the GroEL protein, was demonstrated in the cyanobacterium Anabaena PCC 7120 by using a rabbit anti-GroEL (Escherichia coli) antibody. Western-blot analysis showed a distinct cross-reaction with a protein of approx. 65 kilodaltons, analogous to the Mr of the E. coli homologue. Immunocyto-chemical studies of vegetative cells showed that a chaperonin was localized in both vegetative cells and heterocysts. In vegetative cells cpn60 was primarily detected both in the carboxysomes, and in the cytoplasm, though mainly in the thylakoid region of the latter. In heterocysts, specialized cells for nitrogen fixation, the cpn60 label was prominent and was evenly distributed throughout the cell. These results support recent findings that chaperonins are multifunctional proteins, and extend those findings by demonstrating the occurrence of cpn60 in a prokaryotic cyanobacterium and by raising the possibility of the involvement of this chaperonin in the assembly of heterocystous proteins.

Key words

Anabaena Chaperonin localization GroEL protein Nitrogenase Ribulose-1,5-bisphosphate carboxylase/oxygenase 





relative molecular mass


ribulose-1,5-bisphosphate carboxylase/oxygenase

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Karin M. Jāger
    • 1
  • Birgitta Bergman
    • 2
  1. 1.Botanisches Institut der Tierärztlichen HochschuleHannover 71Germany
  2. 2.Department of Physiological BotanyUniversity of UppsalaUppsalaSweden

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