The relationship between ion mobility and collision cross section of peptides and proteins: an experimental and theoretical study

肽和蛋白质的离子淌度与碰撞截面之间的关系：实验和理论研究

• 批准号: BB/G017441/1
• 金额: $ 9.48万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Training Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FG017441%2F1
• 关键词: relationship; between; ion; mobility; collision

The analytical technique of ion mobility spectrometry was developed by Cohen and Karasek in 1970 as a sensor building on earlier gas-phase ion chemistry investigations. It has since been used to detect a wide range of analytes including illegal drugs, chemical warfare agents, explosives and environmental pollutants. Ion mobility is a measure of how quickly a gas phase ion moves through a buffer gas under the influence of an electric field, and this depends on two factors: the rotationally averaged collision cross section of the ion and the charge present on it. By measuring the drift time of an ion through a known distance it is possible to determine its collision cross section with some degree of accuracy. In instruments where the drift field is a dc potential, the relationship between the collision cross section of an ion and the measured average drift time can be easily found. The experimental collision cross section can be compared to cross sections predicted from co-ordinates obtained from other structural investigations, or from computational measurements to obtain atomistically detailed conformational information. The relationship between the drift times of ions in a ion mobility spectrometer and their gas-phase collision cross section, is well understood, and in recent years ion mobility spectrometry coupled with mass spectrometry (IM-MS) has gained particular importance as a tool for structural analysis and particularly for its use to reveal conformation of biological molecules. After developments in soft ionization methods, IM-MS studies of biological relevant species started in the mid and late 1990's on home built instruments which coupled these two well known analytical techniques. Some of the most influential work in this period was performed by Bowers, Jarrold, Clemmer, and Hill and their investigations have paved the way for others and prompted development of commercially available mobility devices, as the power of this technique for biological analysis became apparent. Waters MS Technologies (Manchester, UK) recently introduced the first commercially available integrated IM-MS instrument the Synapt HDMS. The RF applied to consecutive electrodes in the stacked ring ion guide within the ion mobility separator, provides a potential well which keeps the ions radially confined within the device. In order to propel the ions through the device, a travelling wave comprising a series of transient DC voltages is superimposed on top of the RF voltage, and hence this device is sometimes referred to as a Travelling Wave Ion Guide - TWIG. This voltage is applied sequentially to pairs of ring electrodes providing a potential which can push ions through the device. These commercial available devices have already been used to good effect. Using a TWIG based system, Robinson et al. have assessed conformations of multimeric proteins, and also the disassembly of complexes viewing the partial unfolding of monomer units whilst still retaining some the integrity of the complex. The benefits of the Synapt compared to home built instruments are undisputed, the duty cycles are shorter and the transmission efficiency through this instrument is better than with most home made devices. However, to properly rationalize experimental drift times obtained on Synapt instrumentations in terms of collision cross sections, requires careful calibration with data obtained on a linear ion mobility instrument, such as that developed by Bowers and Clemmer and also present in the lab of Barran. One of the issues with this is that the available collision cross section data for proteins is limited, and also often not well verified. This means that despite the extreme interest in the application of the Synapt to interrogate complex biological structures, and beautiful preliminary work, results are still somewhat 'unverified' This studentship will seek to address this in several ways. See the Research Strategy below.

Cohen和Karasek在1970年开发了离子迁移率的分析技术，作为早期气相离子化学研究的传感器建筑。此后，它被用于检测包括非法药物，化学战剂，炸药和环境污染物在内的广泛分析物。离子迁移率是对气体离子在电场影响下通过缓冲气体移动的速度的量度，这取决于两个因素：离子的旋转平均碰撞横截面以及其上存在的电荷。通过测量离子通过已知距离的漂移时间，可以以一定程度的准确性来确定其碰撞横截面。在漂移场是直流电位的仪器中，可以很容易地找到离子的碰撞横截面与测量平均漂移时间之间的关系。可以将实验碰撞横截面与从其他结构研究获得的坐标预测的横截面进行比较，或从计算测量值中获得的，以获得原子详细的构象信息。人们充分了解了离子迁移率光谱仪中离子的漂移时间与其气相碰撞横截面之间的关系，并且近年来，离子迁移率光谱法以及质谱（IM-MS）的关系非常重要，作为结构分析的工具，尤其是用于揭示生物分子构象的工具。在软电离方法的发展之后，对生物学相关物种的IM-MS研究始于1990年代中期和末期的家庭建造仪器，并结合了这两种众所周知的分析技术。在此期间，一些最有影响力的工作是由鲍尔斯，贾罗尔德，克莱默和希尔进行的，他们的调查为他人铺平了道路，并促使人们开发了商业上可用的流动设备，因为这种生物学分析技术的力量变得显而易见。 Waters MS Technologies（英国曼彻斯特）最近推出了首个商业上可用的IM-MS仪器The Sentapt HDM。 RF应用于离子迁移率分离器中堆叠环离子导向器中的连续电极，提供了一个潜在的孔，可将离子径向限制在设备中。为了通过设备推动离子，包含一系列瞬态直流电压的行驶波叠加在RF电压的顶部，因此该设备有时被称为波动波离子导向 - TWIG。该电压依次应用于一对环电极对，提供的电势可以推动离子通过设备。这些商业可用的设备已被用于良好的效果。 Robinson等人使用基于树枝的系统。已经评估了多聚体蛋白的构象，以及查看单体单元部分展开的复合物的拆卸，同时仍然保留了该复合物的完整性。与自制仪器相比，突触的好处是无可争议的，占空比较短，并且通过该工具的传输效率比大多数自制设备更好。但是，要适当地合理化在碰撞横截面上获得突触仪器上获得的实验漂移时间，需要对在线性离子迁移仪器上获得的数据进行仔细的校准，例如Bowers和Clemmer开发的数据，也存在于Barran实验室中。这样的问题之一是，蛋白质的可用碰撞横截面数据有限，而且通常也无法得到很好的验证。这意味着，尽管对将突触应用于询问复杂的生物结构和精美的初步工作的极大兴趣，但结果仍然有些“未经验证”，该学生会寻求以几种方式解决这一问题。请参阅下面的研究策略。