酸迁移与酸在质子化酸中的损失:一项计算研究
Justin Kai-Chi Lau1,2, Alan C Hopkinson1, K W Michael Siu1,2
1Department of Chemistry and Centre for Research in Mass Spectrometry, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
The journal of physical chemistry. B
|January 8, 2024
概括
计算分析揭示了酸盐组在中的迁移,这是质谱学的关键问题. 本研究阐明了该机制,确定了高能中间体,并将迁移障碍与酸损失进行了比较.
科学领域:
- 计算化学是一种计算化学.
- 生物化学 生物化学
- 质谱测量质量谱测量
背景情况:
- 蛋白质酸化是一种关键的翻译后修饰,调节细胞功能.
- 精确识别酸化部位对于理解细胞信号来说至关重要.
- 在实验分析期间的酸盐群迁移可能导致信号传导研究中的错误结论.
研究的目的:
- 以计算方式检查酸盐组在质子五中的酸盐残留物之间迁移的机制.
- 研究基本氨基酸 (histidine,lysine, arginine) 在迁移过程中的作用.
- 为了比较酸迁移与酸损失的能量障碍.
主要方法:
- 密度函数理论 (DFT) 计算使用B3LYP/6-31G的理论水平.
- 使用M06-2X/6-311++G (d,p) 和MP2/6-31++G (d,p) 级别进行单点能量计算.
- 对较大的 (His-pSer-(Gly) n-Ser-His) 的分析,其链长度不同 (n=2-5).
- 对特定序的新功能M08-HX和MN15进行评估.
主要成果:
- 酸盐迁移涉及一个非同步的过程,与高能量的zwitterionic中间体.
- 酸盐迁移的障碍范围在 219-274 kJ mol-1 (B3LYP/6-31G) 之间.
- 酸损失的障碍与迁移障碍相似,特别是在较小的中.
- 对于较长的 (n=4,5),酸损失障碍明显高于酸迁移障碍.
结论:
- 这项研究提供了在气相条件下对酸中酸群迁移的机制性理解.
- 这些发现为酸盐迁移和联质谱中的其他反应之间观察到的竞争提供了理由.
- 计算洞察力对于解释涉及化的实验结果至关重要.
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