The binding of the B‐chain of ricin to Burkitt lymphoma cells

FEBS Letters

Tonevitsky, Alexander G.¹  Manevich, Efim M.²  Bergelson, Lev D.² 

[1] Cardiological Research Center, USSR Academy of Medical Science, USSR Academy of Sciences, Moscow, USSR;M.M. Shemyakin Institute of Bioorganic Chemistry, USSR Academy of Sciences, Moscow, USSR

关键词: Ricin receptor;    Fluorescent probe;    Sphingomyelin;    (Burkitt lymphoma cell);    RA and RB;    A- and B-chains of ricin;    r;    fluorescence anisotropy;    AMS;    anthrylvinyl-labelled sphingomyelin;    [N-12-(9-anthryl)-11-trans-dodecanoylsphingosine-1-phosphocholine];   

DOI  :  10.1016/0014-5793(86)80108-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

It is shown that conformational changes of receptor proteins brought about by binding of a ligand induce changes in the lipid environment of the receptor that can be monitored by fluorescent lipid probes. On this basis a new approach to studies of ligand-receptor binding is proposed. Using the interaction of the ricin B-chain with Burkitt lymphoma cells as an example and fluorescent labelled sphingomyelin as a probe, the ligand-induced changes of fluorescence anisotropy were shown to be concentration-dependent and to permit determination of the binding constant and the number of receptor-binding sites. The method was found to be specific and highly sensitive, allowing detection of the action of one R_B molecule per cell. Scatchard analysis of the binding of ¹²⁵I-R_B demonstrated the presence on the cell surface of two binding sites with K _d ~ 10⁻¹⁰ and ~ 10⁻⁸ M, respectively. Only the high-affinity sites were detected by the fluorescence technique. Saturation of these sites resulted in maximum inhibition of protein synthesis.

【 授权许可】

Unknown