Cryo-EM reveals the asymmetric assembly of squid hemocyanin

IUCrJ

Stabrin, M.¹  Tanaka, Y.²  Kato, S.³  Matsui, T.⁴  Raunser, S.⁵ 

[1] Faculty of Fisheries, Kagoshima University, Kagoshima 890-0056, Japan;Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan;Japan Science and Technology Agency, PRESTO, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan;Max Planck Institute of Molecular Physiology, Department of Structural Biochemistry, Otto Hahn Strasse 11, Dortmund 44227, Germany;The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0056, Japan

关键词: SINGLE-PARTICLE CRYO-EM;    STRUCTURE DETERMINATION;    CRYO-ELECTRON MICROSCOPY;    MACROMOLECULAR MACHINES;    PROTEIN STRUCTURES;   

DOI  :  10.1107/S205225251900321X

学科分类：数学（综合）

来源: International Union of Crystallography

【 摘 要 】

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.

【 授权许可】

CC BY