Crystallization and preliminary X-ray crystallographic study of a 3.8-MDa respiratory supermolecule hemocyanin

Asuka Matsuno, Zuoqi Gai, Miyuki Tanaka, Koji Kato, Sanae Kato, Tsuyoshi Katoh, Takeshi Shimizu, Takeya Yoshioka, Hideki Kishimura, Yoshikazu Tanaka, Min Yao

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Many molluscs transport oxygen using a very large cylindrical multimeric copper-containing protein named hemocyanin. The molluscan hemocyanin forms a decamer (cephalopods) or multidecamer (gastropods) of approximately 330-450. kDa subunits, resulting in a molecular mass >3.3. MDa. Therefore, molluscan hemocyanin is one of the largest proteins. The reason why these organisms use such a large supermolecule for oxygen transport remains unclear. Atomic-resolution X-ray crystallographic analysis is necessary to unveil the detailed molecular structure of this mysterious large molecule. However, its propensity to dissociate in solution has hampered the crystallization of its intact form. In the present study, we successfully obtained the first crystals of an intact decameric molluscan hemocyanin. The diffraction dataset at 3.0-Å resolution was collected by merging the datasets of two isomorphic crystals. Electron microscopy analysis of the dissolved crystals revealed cylindrical particles. Furthermore, self-rotation function analysis clearly showed the presence of a fivefold symmetry with several twofold symmetries perpendicular to the fivefold axis. The absorption spectrum of the crystals showed an absorption peak around 345. nm. These results indicated that the crystals contain intact hemocyanin decamers in the oxygen-bound form.

Original languageEnglish
Pages (from-to)379-382
Number of pages4
JournalJournal of Structural Biology
Issue number3
Publication statusPublished - Jun 1 2015
Externally publishedYes


  • Crystallization
  • Decamer
  • Hemocyanin
  • Self-rotation function
  • Supermolecule

ASJC Scopus subject areas

  • Structural Biology


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