The shapes and sizes of two domains of tropomodulin, the P‐end‐capping protein of actin‐tropomyosin

FEBS Letters

Maéda, Yuichiro¹  Fujisawa, Tetsuro¹  Kostyukova, Alla¹ 

[1] Laboratory for Structural Biochemistry, RIKEN Harima Institute at SPring-8, 1-1-1 Kouto, Mikazuki, Sayo, Hyogo 679-5148, Japan

关键词: Actin-capping protein;    Tropomyosin-binding protein;    Muscle thin filament;    Actin dynamics;    Small-angle X-ray scattering;   

DOI  :  10.1016/S0014-5793(01)02498-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Tropomodulin, the P-end (slow-growing end)-capping protein of the actin-tropomyosin filament, and its fragment (C20) of the C-terminal half were studied by synchrotron small-angle X-ray scattering, restoring low-resolution shapes using an ab initio shape-determining procedure. Tropomodulin is elongated (115 Å long) and consists of two domains, one of 65 Å in length and the other being similar to C20 in shape and size if the long axes of the two are tilted by about 40° relative to each other. We propose a model for tropomodulin in association with tropomyosin and actin: the N-terminal half of tropomodulin, a rod, binds to the N-terminus of tropomyosin and the C-terminal triangle domain protrudes from the P-end being slightly bent towards the actin subunit at the end, thereby blocking the P-end.

【 授权许可】

Unknown