食品科学

• 基础研究 • 上一篇    下一篇

荧光光谱法研究杆菌肽与溶菌酶的相互作用

倪志华1,2,张玉明1,*,邓传怀1,周艳芬1,2   

  1. 1.河北大学生命科学学院,河北 保定 071002;2.河北省生物工程技术研究中心,河北 保定 071002
  • 出版日期:2016-05-15 发布日期:2016-05-18

Fluorescence Spectroscopic Study of the Interaction of Lysozyme with Bacitracin

NI Zhihua1,2, ZHANG Yuming1,*, DENG Chuanhuai1, ZHOU Yanfen1,2   

  1. 1. College of Life Sciences, Hebei University, Baoding 071002, China;
    2. Research Center of Bioengineering of Hebei Province, Baoding 071002, China
  • Online:2016-05-15 Published:2016-05-18

摘要:

利用荧光光谱法研究了杆菌肽与溶菌酶的相互作用。结果表明:杆菌肽能使溶菌酶的内源荧光发生猝灭。在不同温度下研究杆菌肽对溶菌酶的荧光猝灭作用,证明荧光猝灭机理属于二者形成复合物所引起的静态猝灭。利用Stern-Volmer方程处理实验数据,发现杆菌肽与溶菌酶具有1 个结合位点,并计算得到了不同温度下杆菌肽与溶菌酶的结合常数(KA):3.60×105 (298 K)、1.90×105 (308 K)、4.51×104 L/mol(318 K)。通过计算热力学参数,可知杆菌肽与溶菌酶的相互作用是一个吉布斯自由能降低的自发过程,且二者之间的主要作用力类型是静电作用。三维荧光光谱实验显示,杆菌肽的加入引起溶菌酶构象的变化,表现为蛋白质内部色氨酸残基所处微环境的疏水性降低。

关键词: 杆菌肽, 溶菌酶, 相互作用, 荧光光谱

Abstract:

The interactions between bacitracin and lysozyme were studied by fluorescence spectroscopy. The results showed
that the intrinsic fluorescence of lysozyme could be quenched by bacitracin. The fluorescence quenching of lysozyme
was analyzed at different temperatures. The quenching mechanism was accomplished in a static manner by forming a
bacitracin-lysozyme complex. The binding parameters were determined according to Stern-Volmer equation, and the
thermodynamic parameters were calculated. The results showed that there was only one binding site between bacitracin and
lysozyme. The binding constants (KA) between bacitracin and lysozyme at different temperatures were 3.60 × 105 (298 K),
1.90 × 105 (308 K), and 4.51 × 104 L/mol (318 K), respectively. Thermodynamic analysis indicated that the interaction
process was spontaneous, and electrostatic force might be primarily responsible for the interaction. In addition, the effect
of bacitracin on the conformation of lysozyme was analyzed by three-dimensional fluorescence spectroscopy. The result
indicated that the polarity of the microenvironment around Trp residues decreased.

Key words: bacitracin, lysozyme, interaction, fluorescence spectroscopy

中图分类号: