高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (9): 1927.doi: 10.7503/cjcu20180075

• 分析化学 • 上一篇    下一篇

电喷雾电离质谱法研究影响五肽间非共价作用的主要因素

吴芳玲, 储艳秋(), 陈新, 魏王慧, 丁传凡()   

  1. 复旦大学化学系, 上海 200433
  • 收稿日期:2018-01-22 出版日期:2018-09-07 发布日期:2018-06-11
  • 作者简介:

    联系人简介: 储艳秋, 男, 博士, 副教授, 主要从事物理化学方面的研究. E-mail: chuyq@fudan.edu.cn; 丁传凡, 男, 博士, 教授, 博士生导师, 主要从事质谱方面的研究. E-mail: cfding@fudan.edu.cn

  • 基金资助:
    国家自然科学基金(批准号: 21773035)资助.

Critical Factors Affecting Noncovalent Interaction Between Pentapeptides Explored by Electrospray Ionization Mass Spectrometry

WU Fangling, CHU Yanqiu*(), CHEN Xin, WEI Wanghui, DING Chuanfan*()   

  1. Department of Chemistry, Fudan University, Shanghai 200433, China
  • Received:2018-01-22 Online:2018-09-07 Published:2018-06-11
  • Contact: CHU Yanqiu,DING Chuanfan E-mail:chuyq@fudan.edu.cn;cfding@fudan.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(No. 21773035).

摘要:

采用电喷雾电离质谱法研究了气相中4种五肽[His-Val-Phe-Arg-Lys(HK), Ile-Tyr-Lys-Val-Glu(IE), Val-Glu-Gly-Ile-Tyr(VY) 和 Ala-Thr-Leu-Leu-Ser(AS)]两两之间的非共价相互作用. 将4 种五肽分别以等摩尔比两两混合, 配制得到6组混合溶液. 质谱测试结果显示, 6组混合溶液中均有配合比为1-1 的非共价复合物生成. 将4种五肽按摩尔比1-1-1-1 混合, 充分反应后, 测试了竞争反应的质谱图, 发现AS与VY, IE与VY 反应后生成的复合物信号强度较强. 采用碰撞诱导解离实验测定了复合物的结合强度, 得到碰撞诱导解离残余率(SY, %)及碰撞能量曲线. 碰撞能量(CE50%)结果显示: AS-AS(12.9 eV)~HK-VY(12.8 eV)?IE-IE(18.6 eV)~HK-IE(19.7 eV)~AS-VY(20.7 eV)~IE-VY(20.3 eV)?AS-IE(23.1 eV)~VY-VY(22.3 eV), 这表明复合物的结合强度明显受到五肽中氨基酸残基侧链R 基团的影响, 即R 基团的极性和酸碱性越强, 五肽间反应得到的非共价复合物的结合强度也越强. 将组成4 种五肽样品的13 种氨基酸分别两两混合, 反应后生成复合物利用碰撞诱导解离实验测定了复合物的碰撞能量(CE50%), 得到了复合物结合强度统计图. 经过分析, 推断气相中五肽复合物结合的主要驱动力为氢键和静电引力. 五肽分子的中间氨基酸残基上带有亲水基团氨基、 羧基或羟基的容易形成非共价复合物, 而带有较强疏水基团的2个五肽则不易形成共价复合物.

关键词: 五肽, 电喷雾电离质谱法, 非共价作用, 影响因素, 碰撞诱导解离

Abstract:

The noncovalent interactions between two of the four pentapeptides including His-Val-Phe-Arg-Lys(HK), Ile-Tys-Lys-Val-Glu(IE), Val-Glu-Gly-Ile-Tyr(VY) and(Ala-Thr-Leu-Leu-Ser)(AS) were investigated by electrospray ionization mass spectrometry. The mass spectra show the formation of 1-1 complex by two of the four pentapeptides. The competitive reaction shows mass spectrometric signal for the complex of AS with VY and the complex of IE with VY are more stronger when the four pentapeptides were mixed together. The binding affinities of the complexes were determined by collision induced dissociation(CID) through survival yield vs. collision energy curves. The collision energy(CE50%) order is AS-AS(12.9 eV)~HK-VY(12.8 eV)?IE-IE(18.6 eV)~HK-IE(19.7 eV)~AS-VY(20.7 eV)~IE-VY(20.3 eV)?AS-IE(23.1 eV)~VY-VY(22.3 eV), indicating that the binding affinities of the complexes are apparently affected by side-chain group R of the amino acid residue composing of pentapetides, that is, the binding affinities of the complexes will be stronger with increasing the polarity and basicity of the side-chain R of amino-acid residue. The main driving force for the formation of the complexes should be ionic such as hydrogen-bonding, but not hydrophobic. The satistics of CE50% for the complexes of amino acids which can composed of four pentapeptide samples were plotted, which further confirmed the conclusions based on CID.

Key words: Pentapeptide, Electrospray ionization mass spectrometry, Noncovalent interaction, Influence factor, Collision induced dissociation

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