Dynamics of molecules and ions in the gas phase

气相中分子和离子的动力学

• 批准号: 194328-2006
• 负责人: Thachuk, Mark
• 金额: $ 2.94万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=365397
• 关键词: Dynamics; molecules; ions; gas; phase

The proposal involves projects that study the way ions move in the gas phase, and how the dynamics of this motion can be used to gain information about the structure of an ion, or to manipulate it in space. One major theme examines ions formed from protein complexes.  Experiments have shown that these complexes, in the gas phase, break up into pieces that have unusual charge distributions.  Specifically, the charges do not spread symmetrically among the pieces, as one would expect. The interesting question is, "Why does this happen?". The prevailing mechanism suggests that some proteins in the complex begin to unfold during the break up, and this causes the charge distributions to become asymmetric.  Our goal is to simulate these processes using computers running molecular dynamics codes, in an attempt to understand this mechanism in detail, and to control it.  One important part of this mechanism is the transfer of protons between different parts of the ion.  In the gas phase, the way protons move can be very different than in solution.  However, understanding proton transfer is very important for mass spectrometrists, who currently are using these gas phase species to sequence amino acids, and thus identify the proteins that exist in a cell or other biological sample. A second major theme is concerned with separating ions with different shapes.  The idea is to develop methods that will preferentially separate ions with non-spherical shapes from those that are spherical.  Such a technique would be very powerful for aerosol and atmospheric scientists, who analyze and study the reactions of chemicals in the environment.  Along the same lines, we would like to develop a method to align ions in the gas phase, to aid experiments that probe the reactivity and behaviour of gas phase species.

该提案涉及研究离子在气相中的运动方式，以及如何利用这种运动的动力学来获取离子结构的信息，或在空间中操纵离子。一个主要的主题是检查由蛋白质复合物形成的离子。实验表明，这些配合物在气相中分解成具有不寻常电荷分布的碎片。具体来说，电荷并不像人们所期望的那样在碎片之间对称地分布。有趣的问题是，“为什么会发生这种情况？”普遍的机制表明，复合物中的一些蛋白质在分解过程中开始展开，这导致电荷分布变得不对称。我们的目标是用运行分子动力学代码的计算机模拟这些过程，试图详细了解这一机制，并控制它。这个机制的一个重要部分是质子在离子的不同部分之间的转移。在气相中，质子的运动方式与溶液中的非常不同。然而，了解质子转移对于质谱专家来说是非常重要的，他们目前正在使用这些气相物质对氨基酸进行测序，从而识别存在于细胞或其他生物样品中的蛋白质。第二个主要主题是关于分离不同形状的离子。这个想法是开发一种方法，可以优先分离非球形和球形的离子。对于分析和研究环境中化学物质反应的气溶胶和大气科学家来说，这种技术将非常有用。沿着同样的思路，我们想开发一种在气相中排列离子的方法，以帮助探测气相物种的反应性和行为的实验。