电喷雾质谱研究乙腈诱导的溶菌酶的构象变化  

Acetonitrile-induced Conformational Transitions of Lysozyme Studied by Electrospray Ionization Mass Spectrometry

作　　者：潘婷婷[1] 储艳秋[1] 张剑霞[1] 吴波[1] 吴梁[1] 丁传凡[1] 

机构地区：[1]复旦大学化学系物理化学研究所,上海200433

出　　处：《复旦学报（自然科学版）》2008年第4期449-453,460,共6页Journal of Fudan University：Natural Science

基　　金：国家自然科学基金资助项目(20473020)

摘　　要：首次采用电喷雾质谱结合圆二色性光谱以及荧光光谱,研究不同浓度的乙腈诱导对溶菌酶构象变化的影响.在pH2.0的酸性环境下,随着乙腈浓度的上升,电喷雾质谱的谱图中溶菌酶电荷状态分布会变宽,当乙腈浓度达到70%时,会出现15+的高电荷离子峰,电荷中心也从纯水溶剂的10+到了12+,表明其三级结构发生了变化,即由天然构象转变为部分非折叠的构象.圆二色光谱显示在溶菌酶水溶液中加入乙腈,二级结构中无规卷曲的百分含量在增加.荧光光谱进一步证明在乙腈的作用下,溶菌酶由天然构象转变为部分非折叠的构象.The effect of acetonitfile-induced conformatk）nal transitions of lysozyme was investigated by electrospray mass spectrometry（ESI-MS） as well as circular dichroiml（CD）spectra and fluorescent spectra. At pH 2, with increasing the acetonitrile concentration, the ESI-MS spectrum showed the range of charge state distribution became wider and the charge state distribution center moved from 10 ＋ in the pure water solvent to 12 ＋ in the 70 % acetonitrile solvent. Furthermore, higher charge state ions such as 15 ＋ were observed when the acetonitrile concentration was increased to 70 %. These results indicated that the tertiary structure of lysozyme had changed, implying that its native conformation had become partially unfolding conformation. According to CD spectra, there was only slight increasing of the ratio of random coil and no obvious change was found in the secondary structure of lysozyme. The fluorescent spectra further confirmed the conclusion which was obtained from ESI-MS spectra.

关 键 词：溶菌酶 乙腈 电喷雾质谱 构象 

分 类 号：O646.54[理学—物理化学]