稀土离子对钙调蛋白与蜂毒素作用的影响

Effects of Rare Earth Ions on the Interaction between Calmodulin and Melittin

分别用钙调蛋白和蜂毒素的内源荧光光谱以及铽离子的敏化荧光光谱考察了铽离子对钙调蛋白构象变化以及对钙调蛋白与蜂毒素相互作用的影响 .结果表明 ,铽离子首先结合在钙调蛋白的第Ⅰ和第Ⅱ位点 ,铽离子不影响钙调蛋白与蜂毒素的相互作用 ,蜂毒素与钙调蛋白作用后不影响铽离子在钙调蛋白上的键合顺序 .傅里叶变换红外光谱结果表明三价的镧离子与钙调蛋白作用使钙调蛋白的α螺旋结构增加 ,β折叠结构减少 ,与钙离子对它的二级结构影响相类似 .稀土离子在钙调蛋白 -蜂毒素复合体系中主要与钙调蛋白作用 .

The effects of terbium ion on the conformation of calmodulin and on the interaction between calmodulin and melittin have been studied by the endogenous fluorescent spectrometry of calmodulin and melittin,and the sensitized fluorescent spectrometry of terbium ion,respectively.The results show that terbium ions have a tight binding site in the I and II metal_binding sites of calmodulin.The conformation of calmodulin induced by terbium ion can bind melittin and transfer the tryptophane residue of melittin to a relatively hydrophobic environment,while the binding of melittin to calmodulin produces effect on the binding orders of terbium ion in camodulin.Results from FT_IR spectrometry have revealed that upon binding of lanthanum ion,apo_calmodulin undergoes a conformational change with the increase of α_helix content and the decrease of β_sheet content.Melittin's binding to calmodulin has no effect on its conformation induced by the binding of lanthanum ion to calmodulin.