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Updated: Jul 31, 2026

Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
1H NMR and spin-labeled EPR studies on the interaction of calmodulin with jujuboside A
1Department of Biological Sciences & Biotechnology, Tsinghua University, Beijing, People's Republic of China.
Abstract:
Jujuboside A (JuA), an effective component of sanzaoren, a Chinese herbal medicine, is a noncompetitive inhibitor of calmodulin (CaM). The interaction of JuA with CaM has been investigated with 1H NMR and spin-labeled EPR spectroscopies. The 1H NMR experiments showed that JuA has two kinds of binding sites on CaM: one locates in the N-terminus, the other locates in the C-terminal region of the polypeptide chain. The EPR studies on 3-maleimido-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl labeled CaM (spin-labeled CaM) revealed that each CaM molecule can bind at least two JuA molecules. Binding of JuA affects the environments of some lysine residues (most likely Lys-74 and Lys-94), suggesting that JuA binds to CaM through hydrophobic interaction.
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