Matrix-Assisted Laser Desorption Ionization for Systems of Large Complexity Modeled by Molecular Dynamics

乔治华盛顿大学的Akos Vertes和弗吉尼亚大学的Robert约翰逊得到了理论和计算化学项目的资助，以进行基质辅助激光解吸电离的分子动力学模拟。 他们将模拟小分子主体基质和水冰基质中的小分子客体的消融。 模拟将采用具有新衍生力场的现实大分子系统，以及具有更精确的非谐势的小分子系统。 选择红外激发，电荷状态，激发密度和外部电场的影响将被调查。最准确的光谱方法取决于在气相中的主题分子。 大的生物分子很难蒸发，因为它们在达到高温之前往往会分解。 最近的一项实验技术称为基质辅助激光解吸电离，通过将大分子嵌入到易于蒸发的基质中，可以通过脉冲激光辐射激发，从而绕过了这个问题。 该方法在大蛋白质的分子量测定中提供了前所未有的准确性。 尽管这种方法有很多优点，但对基本过程的了解仍然滞后。 对所涉及的基本现象的更好理解将有助于将这种技术的能力扩展到重要的新类别的生物分子。

Akos Vertes of George Washington University and Robert Johnson of the University of Virginia are supported by a grant from the Theoretical and Computational Chemistry Program to pursue molecular dynamics simulations of matrix-assisted laser desorption ionization. They will simulate ablation of small macromolecular guests from small molecule host matrices and water ice matrices. The simulations will employ realistic large-molecule systems with newly derived force fields, and small-molecule systems with more accurate anharmonic potentials. The effects of selected infrared excitation, charge states, excitation density, and external electric fields will be investigated.The most accurate spectroscopic methods depend on the subject molecules being in the gas phase. Large biomolecules are difficult-to-impossible to evaporate since they tend to decompose before reaching high temperatures. A recent experimental technique called matrix-assisted laser desorption ionization bypasses this problem by embedding large molecules into an easy-to-evaporate matrix that can be excited by pulsed laser radiation. This method provides unprecedented accuracy in the molecular mass determination of large proteins. Despite the advantages of this method, knowledge of the underlying processes is lagging. Improved understanding of the basic phenomena involved will help extend the capabilities of this technique to important new classes of biomolecules.