朊病毒蛋白113-120序列多肽的反相液相色谱保留行为与构象稳定性的关系

摘　要：朊病毒(Prion)蛋白是人和动物慢性中枢神经系统退化病的传染源，该蛋白的113-120序列被认为在其致病和传染机理中起着重要作用。以反相高效液相色谱为分析手段，研究了Prion蛋白113-120序列多肽的色谱保留行为。通过比较不同温度、不同流动相条件下该多肽色谱保留行为的变化，发现在以乙腈溶液为流动相时，lnKw随温度的变化关系和Van′tHoff曲线均比较简单，说明该多肽在乙腈溶液中所采取的构象均较稳定，不易受温度的影响。以甲醇溶液为流动相时，具有游离末端的多肽的lnKw随温度变化关系和Van′tHoff曲线比末端羧基和氨基分别被酰胺封闭的多肽要复杂，说明具有游离末端的多肽在甲醇溶液中所采取的构象相对较不稳定，易受环境的影响。这些结果进一步证明，113-120序列在Prion蛋白构象变化中可能起着重要作用。

关键词：朊病毒蛋白，反相高效液相色谱，色谱保留行为，多肽构象

分类号：065　文献标识码：A

The Relationship Between the Reversed　Phase High　Performance Liquid Chromatographic Retention Behavior of Prion 113-120 Peptide and Stability of Conformation

Milton T.W. Hearn（Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168，Australia）　
Balvant Sitaram（Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168，Australia）　
Guo Minliang（College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009）　
Milton T. WHearn（Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia）　
Balvant Sitaram（Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia）　

Abstract：Prions are the infectious agents of the transmissible spongiform encephalopathies. The sequence 113-120 of Prion proteins is thought to be the most highly amyloidogenic peptide. The chromatographic retention behaviors of Prion 113-120 peptide on C18-column were studied under reversed-phase high-performance liquid chromatographic conditions with isocratic elution. When aquo-acetonitrile mobile phases were used, the temperature-depending relationships of lnkw and Van′t Hoff plots of both peptides with free termini and with capped termini were simple. The results demonstrated that the conformations adopted by both peptides in aquo-acetonitrile mobile phases were relatively stable, and could not be perturbed by temperature. When aquo-methanol mobile phases were used, the temperature-depending relationships of lnkw and Van′t Hoff plots of peptide with free termini were more complicated than that of peptide with capped termini. These results demonstrated that the conformations adopted by peptide with free termini in aquo-methanol mobile phases were relatively unstable and could be perturbed by circumstance. All these results further demonstrate that the sequence 113-120 could play an important role in the conformational change of Prion proteins.
Keywords：Prion protein, reversed-phase high performance liquid chromatography, chromatographic retention behavior, peptide conformation

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收稿日期：2000年7月28日

修稿日期：2000年12月18日

出版日期：2001年6月1日