1H NMR and spin-labeled EPR studies on the interaction of calmodulin with jujuboside A.
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.
Department of Biological Sciences & Biotechnology, Tsinghua University, Beijing, People's Republic of China.
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Zhou
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Li
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Wang
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Ou
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Zhou
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism; D002240:Carbohydrate Sequence; D002417:Cattle; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D006993:Hypnotics and Sedatives / Q000737:chemistry; D007700:Kinetics; D008239:Lysine; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D012503:Saponins / Q000737:chemistry* / Q000378:metabolism; D013113:Spin Labels
D002147:Calmodulin; D006993:Hypnotics and Sedatives; D012503:Saponins; D013113:Spin Labels; C087808:jujuboside A; D008239:Lysine