Interaction of isoforms of S100 protein with smooth muscle caldesmon

FEBS Letters

Marston, Steven B¹  Gusev, Nikolai B²  Polyakov, Alexei A²  Huber, Pia A.J¹ 

[1] Imperial College, National Heart and Lung Institute, Dovehouse Street, London SW3 6LY, UK;Department of Biochemistry, School of Biology, Moscow State University, Moscow 119899, Russia

关键词: Caldesmon;    S100;    Calmodulin;    EF-hand protein;    Actomyosin;    DTNB;    5;    5′-dithiobis(nitrobenzoic) acid;    EGTA;    ethyleneglycoltetraacetate;    TCA;    trichloroacetic acid;    SDS;    sodium dodecyl sulfate;   

DOI  :  10.1016/S0014-5793(98)00014-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Interaction of S100a and S100b with duck gizzard caldesmon was investigated by means of native gel electrophoresis, fluorescent spectroscopy and disulfide crosslinking. Both isoforms of S100 interact with intact caldesmon and its C-terminal deletion mutant 606C (residues 606–756) with apparent K _d of 0.2–0.6 μM thus indicating that the S100-binding site is located in the C-terminal domain of caldesmon. The single SH group of duck gizzard caldesmon can be crosslinked to Cys-84 of the β-chain or to Cys-85 of the α-chain of S100. Crosslinking of S100 reduces the inhibitory action of caldesmon on actomyosin ATPase activity. S100 reverses the inhibitory action of intact caldesmon and its deletion mutants 606C (residues 606–756) and H9 (residues 669–737) as effectively as calmodulin. S100a has higher affinity to caldesmon and is more effective than S100b in reversing caldesmon-induced inhibition of actomyosin ATPase activity. Although monomeric (calmodulin, troponin C) and dimeric (S100) Ca-binding proteins have different sizes and structures they interact with caldesmon in a very similar fashion.

【 授权许可】

Unknown