Characterization of a peptide family from the skin secretion of the Middle East Tree Frog Hyla savignyi by composition-based de novo sequencing
Characterization of a peptide family from the skin secretion of the Middle East Tree Frog Hyla savignyi by composition-based de novo sequencing
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DOI：
10.1002/rcm.4717
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发表时间：
2010-10-15
影响因子：
2
通讯作者：
Spengler, Bernhard
中科院分区：
文献类型：
--
作者：
Langsdorf, Markus;Ghassempour, Alireza;Spengler, Bernhard
在树蛙皮肤分泌物中发现了一个新的色氨酸样肽家族。肽通过数据库独立的测序策略进行表征，并研究了特定的离子片段特征。采用轻度电刺激法采集海葵标本的皮肤分泌物。利用反相纳米高效液相色谱（nanoHPLC）分离多肽，利用电喷雾电离傅立叶变换离子回旋共振质谱（FTICR-MS）在线获取质谱。通过人工从头测序和基于成分的测序（CBS）对肽进行了表征，发现其主要为c端游离酸及其酸酰胺类似物。酰胺肽在碰撞诱导解离（CID）后产生的y型离子强度低于它们的酸类似物。提出了内部b离子形成（正离子模式）和CO2消除（负离子模式）的机制。我们还举例说明了脯氨酸效应和序列重排后非直接序列离子的形成等现象。重排产物、内部离子和脯氨酸效应的出现使得CID光谱非常复杂。然而，CBS分析的结果是成功的和高度可靠的序列分析。版权所有John Wiley & Sons， Ltd。
A new tryptophyllin-like peptide family was found in the skin secretion of the tree frog Hyla savignyi. Peptides were characterized by database-independent sequencing strategies and specific ion fragmentation features were investigated. Skin secretions from specimens of Hyla savignyi were collected by mild electrical stimulation. Peptides were separated by reversed-phase nano-high-performance liquid chromatography (nanoHPLC) and mass spectra were acquired online by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Peptides were characterized by manual de novo sequencing and by composition-based sequencing (CBS), appearing mostly as C-terminal free acids and as their acid amide analogs. Amide peptides yielded lower intensities of y-type ions after collision-induced dissociation (CID) than their acid analogs. A mechanism of internal b-ion formation (positive ion mode) and of CO2 elimination (negative ion mode) is proposed. We also exemplified phenomena such as the proline effect and formation of nondirect sequence ions after sequence rearrangements. The occurrence of rearrangement products, of internal ions and of the proline effect made the CID spectra highly complex. CBS analysis nevertheless resulted in successful and highly reliable sequence analysis. Copyright (c) 2010 John Wiley & Sons, Ltd.