【摘要】 在0.01 mol·L-1Hepes,0.15 mol·L-1Na Cl,p H 7.4及室温条件下,采用紫外差光谱和荧光光谱的方法研究了稀土离子Ho(III),Er(III),Yb(III)与八肋游仆虫中心蛋白N端半分子(N-terminal domain of Euplotes octocarinatus centrin,N-Eo Cen)的结合性质。结果表明:稀土离子Ho(III),Er(III),Yb(III)与N-Eo Cen结合导致蛋白质高级结构发生明显变化,疏水区暴露增加。二甲酚橙为竞争配体测得稀土离子Ho(III),Er(III),Yb(III)与N-Eo Cen两个位点的结合能力分别为:lg KI,Ho(III)=5.47±0.37,lg KII,Ho(III)=5.07±0.45;lg KI,Er(III)=5.78±0.42,lg KII,Er(III)=5.36±0.52;lg KI,Yb(III)=5.80±0.65,lg KII,Yb(III)=5.37±0.61。更多还原

【Abstract】 The binding of Ho( III),Er( III),Yb( III) with the N-terminal domain of Euplotes octocarinatus centrin( N-Eo Cen) were investigated by fluorescence spectra and difference UV-Vis spectra in 0. 01 mol·L- 1Hepes,0. 15 mol·L- 1Na Cl at p H 7. 4 and room temperature. Lanthanide including Ho( III),Er( III),Yb( III) binding with N-Eo Cen resulted in the conformation of N-Eo Cen changed from closed state to open state and was accompanied by enhancement of the exposed hydrophobic surfaces. Using xylenol orange as luminescent and competitive ligand,the conditional binding constants of site I and II on N-Eo Cen with Ho( III),Er( III) and Yb( III) were calculated to be lg KI,Ho( III)= 5. 47 ± 0. 37,lg KII,Ho( III)= 5. 07 ± 0. 45; lg KI,Er( III)= 5. 78 ± 0. 42,lg KII,Er( III)= 5. 36 ±0. 52; lg KI,Yb( III)= 5. 80 ± 0. 65,lg KII,Yb( III)= 5. 37 ± 0. 61,respectively.更多还原