高等学校化学学报Issue(1)：37-47,11.DOI:10.7503/cjcu20130721
气相中碱金属离子与丝氨酸、亮氨酸和赖氨酸五肽复合物的裂解反应
Fragmentation Reactions of Complexes of Alkali Metal Ions with Pentaserine, Pentaleucine and Pentalysine in Gas Phase
摘要
Abstract
For exploring the effects of alkali metal ions on the dissociations of peptides with different side chains in the gas phase, the complexes of Li+, Na+, K+, Rb+ and Cs+ with pentapeptides, Ser-Ser-Ser-Ser-Ser( S5 ) , Leu-Leu-Leu-Leu-Leu ( L5 ) and Lys-Lys-Lys-Lys-Lys ( K5 ) , were chosen to investigate the frag-mentation reaction pathways by mass spectrometry. The experimental results indicated that alkali metal ions and S5, L5, K5 can form 1:1 and 2:1 non-covalent complexes in the gas phase, and the binding strength between alkali metal ions and pentapeptides descend with the increasing of the radii of alkali metal ions. Quantitative analyses of mass spectra demonstrated that the binding constants for the complexes of K+with S5 , L5 and K5 are 8.94í104 , 2.83í104 and 2.50í103 L/mol, respectively, revealing that the binding strength of complexes decrease in order of S5 , L5 and K5 . The analyses of the fragment ions arising from the complexes of alkali metal ions with pentapeptides showed that the dissociations mainly occur in the backbones of the pep-tides. Among three pentapeptides, the complexes of pentaserines are the easiest to fragment, pentaleucines take second place, while pentalysines are the hardest. The dissociations also occur in the side chains, and there are significant differences among the three complexes. Moreover, the relationships among various frag-ment ions arising from the complex of Na+ with L5 were tested. Based on the theoretical model of Dunbar, it was proposed that in the fragmentation process, the alkali metal ion may shift to the N- or C-terminal of the pentapeptide. In 2:1 complex, the first alkali metal ion may conjugate to the carbonyl groups of four amides, while the second one may conjugate to the oxygen atoms of carboxyl group of the pentapeptide.关键词
质谱法/碰撞诱导解离/碱金属离子/五肽/裂解反应Key words
Mass spectrometry/Collision induced dissociation/Alkali metal ion/Pentapeptide/Fragmenta-tion reaction分类
化学化工引用本文复制引用
魏王慧,王青,储艳秋,汪日志,丁传凡..气相中碱金属离子与丝氨酸、亮氨酸和赖氨酸五肽复合物的裂解反应[J].高等学校化学学报,2014,(1):37-47,11.基金项目
国家科技支撑计划项目(批准号:2009BAK60B03)、国家重大科学仪器设备开发专项项目(批准号:2011YQ090005)和上海市分子催化和功能材料重点实验室高级访问学者基金(批准号:13FG081)资助.@@@@ Supported by the National Science and Technology Pillar Program of China(No.2009BAK60B03), the National Major Scientific Instrument, Equipment Development Project of China(No.2011YQ090005) and the Senior Visiting Scholar Foundation for Shanghai Key Laboratory of Molecu-lar Catalysts and Innovative Materials, Shanghai, China(No.13FG081) （批准号:2009BAK60B03）
