Cryo-EM reveals the asymmetric assembly of squid hemocyanin

Yoshikazu Tanaka, Sanae Kato, Markus Stabrin, Stefan Raunser, Takashi Matsui, Christos Gatsogiannis

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


The oxygen transporter of molluscs, hemocyanin, consists of long pearl-necklace-like subunits of several globular domains. The subunits assemble in a complex manner to form cylindrical decamers. Typically, the first six domains of each subunit assemble together to form the cylinder wall, while the C-terminal domains form a collar that fills or caps the cylinder. During evolution, various molluscs have been able to fine-tune their oxygen binding by deleting or adding C-terminal domains and adjusting their inner-collar architecture. However, squids have duplicated one of the wall domains of their subunits instead. Here, using cryo-EM and an optimized refinement protocol implemented in SPHIRE, this work tackled the symmetry-mismatched structure of squid hemocyanin, revealing the precise effect of this duplication on its quaternary structure and providing a potential model for its structural evolution.

Original languageEnglish
Pages (from-to)426-437
Number of pages12
Publication statusPublished - 2019


  • cryo-electron microscopy
  • macromolecular machines
  • protein structures
  • single-particle cryo-EM
  • structure determination

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry
  • Materials Science(all)
  • Condensed Matter Physics


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