Structural characterization of methionine and leucine enkephalins by hydrogen/deuterium exchange and electrospray ionization tandem mass spectrometry
Structural characterization of methionine and leucine enkephalins by hydrogen/deuterium exchange and electrospray ionization tandem mass spectrometry
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DOI：
10.1002/rcm.1739
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发表时间：
2005-01-01
影响因子：
2
通讯作者：
Dass, C
中科院分区：
文献类型：
--
作者：
Cai, XM;Dass, C
使用氢/氘交换 (HDX) 结合电喷雾电离 (ESI) 质谱法鉴定了三氟乙醇 (TFE) 诱导的两种内源性阿片活性五肽甲硫氨酸脑啡肽 (Met-enk) 和亮氨酸脑啡肽 (Leu-enk) 的构象变化。通过获取氘代肽的串联质谱来表征各个氨基酸残基的交换特征。 HDX 中涉及的不稳定氢的确切身份表明，两种肽的单体形式在水性溶剂中均采用展开构象，但在膜模拟环境下更倾向于 5→2 β 转角二级结构。 Met-enk和Leu-enk的ESI质谱也表明这些肽的二聚体结构与单体构象共存。二聚体结构的程度取决于肽浓度和溶剂的性质。非极性溶剂有利于二聚体的形成。版权所有 (C) 2004 John Wiley Sons, Ltd.
Conformational changes in two endogenous opioid active pentapeptides methionine enkephalin (Met-enk) and leucine enkephalin (Leu-enk) induced by trifluoroethanol (TFE) were identified using hydrogen/deuterium exchange (HDX), coupled with electrospray ionization (ESI) mass spectrometry. The exchange features in individual amino acid residues were characterized by acquiring tandem mass spectra of the deuterated peptides. The exact identity of the labile hydrogens involved in HDX reveals that the monomer forms of both peptides adopt an unfolded conformation in aqueous solvent, but prefer the 5 --> 2 beta-turn secondary structure under the membrane-mimetic environment. The ESI mass spectra of Met-enk and Leu-enk also reveal that the dimer structure of these peptides coexists with the monomer conformation. The extent of the dimer structure is dependent on the peptide concentration and nature of the solvent. The non-polar solvents facilitate the dimer formation. Copyright (C) 2004 John Wiley Sons, Ltd.