Crystal Structure of the 3.8-MDa Respiratory Supermolecule Hemocyanin at 3.0 Å Resolution

Zuoqi Gai, Asuka Matsuno, Koji Kato, Sanae Kato, Md Rafiqul Islam Khan, Takeshi Shimizu, Takeya Yoshioka, Yuki Kato, Hideki Kishimura, Gaku Kanno, Yoshikatsu Miyabe, Tohru Terada, Yoshikazu Tanaka, Min Yao

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


Summary Molluscan hemocyanin, a copper-containing oxygen transporter, is one of the largest known proteins. Although molluscan hemocyanins are currently applied as immunotherapeutic agents, their precise structure has not been determined because of their enormous size. Here, we have determined the first X-ray crystal structure of intact molluscan hemocyanin. The structure unveiled the architecture of the 3.8-MDa supermolecule composed of homologous functional units (FUs), wherein the dimers of FUs hierarchically associated to form the entire cylindrical decamer. Most of the specific inter-FU interactions were localized at narrow regions in the FU dimers, suggesting that rigid FU dimers formed by specific interactions assemble with flexibility. Furthermore, the roles of carbohydrates in assembly and allosteric effect, and conserved sulfur-containing residues in copper incorporation, were revealed. The precise structural information obtained in this study will accelerate our understanding of the molecular basis of hemocyanin and its future applications.

Original languageEnglish
Pages (from-to)2204-2212
Number of pages9
Issue number12
Publication statusPublished - Dec 1 2015
Externally publishedYes

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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