Structure of holo‐chaperonin studied with electron microscopy Oligomeric cpn10 on top of two layers of cpn60 rings with two stripes each

FEBS Letters

Ishii, Noriyuki¹  Taguchi, Hideki¹  Yoshida, Masasuke¹  Sumi, Masato¹ 

[1] Laboratory of Resources Utilization R-1, Department of Life Science, Tokyo Institute of Technology, Nagatsuta 4259, Yokohama 227, Japan

关键词: Chaperonin;    Holo-chaperonin;    Electron microscopy;    Thermus thermophilus;    cpn60 and cpn10;    polypeptides of approximate molecular weights 60 and 10 kDa;    respectively;    which are included in holo-chaperonin;    [cpn60]7;    a ring made from seven cpn60 monomers;    [cpn60]14;    a tetradecamer of cpn60;    stacked rings of two [cpn60]7;   

DOI  :  10.1016/0014-5793(92)80240-H

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A structural model of holo-chaperonin, known as a protein-folding control protein comprising 60 kDa (cpn60) and 10 kDa polypeptides (cpn10), is proposed based on the electron microscopic images of holo-chaperonin from Thermus thermophilus and cpn60 from Paracoccus denitrificans. Isolated Paracoccus cpn60 shows very similar images to those of Escherichia coli tetradecameric cpn60, a seven-membered ring in the top view and a rectangular shape with four stripes in the side view. However, a small number of half-thick rectangles with two stripes are also seen which indicates that a single cpn60-heptamer ring has two stripes parallel to the plane of the ring. Thermus holo-chaperonin shows a bullet-like shape in the side view, and antibory against cpn10 binds only to the round side of the bullet. We conclude that a single cpn60-heptamer ring with two stripes stacks into two layers, and a cpn10 oligomer binds to one side of the layers.

【 授权许可】

Unknown