气态m-氨基酸的化:离子与中性结合和水桥
Terrence M Chang1, Satrajit Chakrabarty, Evan R Williams
1Department of Chemistry, University of California , Berkeley, California 94720-1460, United States.
Journal of the American Chemical Society
|June 28, 2014
概括
水分子在m-aminobenzoic酸集群中优先水质化质子胺,而不是碳素酸. 随着更多的水,与碳酸的结发生,影响同位素稳定性和解离障碍.
科学领域:
- 物理化学 物理化学
- 频谱学是一种光谱学.
- 计算化学的计算化学
背景情况:
- 了解生物分子的水合对于生物过程至关重要.
- 质子氨基酸由于充电和中性功能组而存在复杂的水合挑战.
- 研究水与质子化m-aminobenzoic acid (MABAH(+)) 的相互作用,可以了解基本的水化机制.
研究的目的:
- 为了研究MABAH中质子胺和中性碳酸基的水合.
- 确定水-MABAH ((+) 集群的结构偏好和能量差异.
- 为水与生物分子相互作用的理论模型建立基准.
主要方法:
- 红外光分离光谱检测集群结构.
- 激光诱导解离动力学来测量异构体群和能量障碍.
- 计算化学 (B3LYP/6-31+G**和MP2/6-31+G**) 用于计算能量和结构.
主要成果:
- 水最初不会在小MABAH中与碳酸质子结合{+) ·{H2O) 1-5团.
- 对于MABAH ((+) · ((H2O) 6) 和更大的,水与碳酸质子结合,形成一个稳定的异构体.
- 与键结合的异构体在能量方面受到青 (能量≥0.5kJmol (-1) 较低),在特定条件下构成>74%的人口.
结论:
- 水解最好发生在与碳酸的显著相互作用之前的质子胺部位.
- 功能组之间的水桥起影响同位素稳定性和解离路径.
- 实验和计算结果为理论水化模型提供了严格的基准.
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