CAJ | 학술논문

基质辅助激光解吸电离-串联飞行时间质谱( MALDI-TOF/TOF)产生的亚胺离子可以提供丰富的肽段组成信息，该方法通常用于基于数据库搜索的蛋白质鉴定，或者结合化学衍生法用于从头测序，因而在一定程度上限制了对亚胺离子的认识及应用。本研究利用239个串联质谱探索MALDI-TOF/TOF 中亚胺离子的断裂特征以及它们在肽段鉴定中的应用，发现在高能碰撞诱导解离条件下组氨酸等14种氨基酸可产生较强的亚胺离子信号(>50%阳性率)，氨基酸的化学结构、位置效应和氨基酸残基个数是影响碎片离子强度的主要因素。此外，探讨了亚胺离子应用过程中的假阳性问题，提出亚胺离子相对强度的比较可以降低假阳性和提高肽段鉴定确定度，有助于完善目前的数据库搜索算法和辅助从头测序分析。
기질보조격광해흡전리-천련비행시간질보( MALDI-TOF/TOF)산생적아알리자가이제공봉부적태단조성신식，해방법통상용우기우수거고수색적단백질감정，혹자결합화학연생법용우종두측서，인이재일정정도상한제료대아알리자적인식급응용。본연구이용239개천련질보탐색MALDI-TOF/TOF 중아알리자적단렬특정이급타문재태단감정중적응용，발현재고능팽당유도해리조건하조안산등14충안기산가산생교강적아알리자신호(>50%양성솔)，안기산적화학결구、위치효응화안기산잔기개수시영향쇄편리자강도적주요인소。차외，탐토료아알리자응용과정중적가양성문제，제출아알리자상대강도적비교가이강저가양성화제고태단감정학정도，유조우완선목전적수거고수색산법화보조종두측서분석。
One of significant characteristics of matrix-assisted laser desorption/ionization tandem time of flight mass spectrometry ( MALD-TOF/TOF ) high-energy collision induced dissociation ( CID ) is to produce abundant immonium ( IM ) ions that can offer a wealth of information for peptide composition. However, MALDI-TOF/TOF is generally used for routine protein identification based on database search or de novo sequencing combined with chemical derivation. Consequently, the characteristics of IM ions may not be fully explored and utilized. Here, a total of 239 MS/MS spectra are used to explore the fragmentation features of IM ions with MALDI TOF/TOF spectrometry and their application for peptide identification. IM ion signals can be observed for 14 kinds of amino acids including histidine etc with a positive rate of more than 50%. We have found that the chemical nature of the amino acids and position effects are the two main factors that affect the intensity of fragment ions. In addition, false positive IM ions are mainly derived from Arg, Lys, Leu and Ile residues or mixture peptides. Besides the compositional information, partial sequence information can also be obtained by a comparison of the relative intensity of IM ions. These findings are helpful when performing manual interpretations and could be useful for improving current peptide search algorithms.