灵菌红素与肌红蛋白相互作用的光谱分析

Spectroscopic Analysis of the Interaction of Prodigiosin with Myohemoglobin

利用紫外-可见吸收光谱、荧光光谱、同步荧光光谱、红外光谱和圆二色谱研究灵菌红素(PG)与肌红蛋白(Mb)的相互作用。结果表明:PG使Mb的紫外吸收增强,说明PG主要与Mb分子外部的氨基酸残基发生了相互作用;Mb的特征荧光峰增强,且随着温度升高结合常数下降,由热力学方程计算出ΔH为-25.293kJ/mol,ΔS分别为-10.238J/(mol.s)(298K)和-10.239J/(mol.s)(310K),得出二者之间的作用力为范德华力;同步荧光光谱表明,PG与Mb相互作用,改变了氨基酸残基的微环境;红外光谱(FT-IR)结果表明PG与Mb多肽链中的酰胺基发生了相互作用,改变了蛋白的二级结构;圆二色谱结果表明PG诱导Mb的二级结构发生改变,α-螺旋含量减少。

The interaction between myohemoglobin（Mb） and prodigiosin（PG） was investigated by UV-visible,fluorescence,synchronous fluorescence,FT-IR and circular dichroism（CD） spectroscopic techniques.The UV absorption of Mb was increased in the presence of PG,indicating that PG interacted mainly with amino acid residues on the outside of Mb.The peak fluorescence intensity of Mb was increased through its interaction with PG.Moreover,the binding constant between them was decreased with increasing temperature.The enthalpy change（ΔH） was-25.293 kJ/mol,and the entropy change（ΔS） was-10.238 J/（mol？s） at 298 K and-10.239 J/（mol？s） at 310 K as calculated according to the thermodynamic equation.The data showed that Van der Waals force played a critical role in the interaction between Mb and PG.Synchronous fluorescence spectroscopic analysis revealed alteration of the microenvironment of amino acid residues as a result of the interaction between both materials.FT-IR analysis showed alternation of the secondary structure of Mb induced by the interaction of amide groups in its polypeptide chains with PG.CD analysis demonstrated a reduction in α-helix content of Mb due to PG-induced alteration of the secondary structure.