Analysis of large biomolecules and biomolecular complexes by TOF mass spectrometry

拟议的研究计划旨在发展改进的质谱方法，以识别和表征大型生物分子和生物分子复合物。这些方法将应用于各种生物问题，使用创新设计的飞行时间（TOF）质谱仪，在我们自己的实验室建造，或与我们的研究伙伴MDS Sciex合作。科学方法利用TOF仪器测量质量的优势，包括有效的无限m/z范围，快速响应和高灵敏度。我们的实验室有电喷雾和MALDI（基质辅助激光解吸/电离）离子源耦合到TOF质谱仪；这两种技术通常提供关于生物分子的互补信息。我们计划继续我们广泛的蛋白质和肽测序计划，使用混合QqTOF质谱仪（Sciex和我们合作设计的成果），它有一个新的目标组件，可以在计算机控制下以更高的速度和精度定位MALDI目标上的点。这种测量通常遵循复杂生物混合物的离线色谱分离。我们还计划将最近发现的电子捕获方法与我们实验室中更新的TOF仪器相结合，如随附的“研究工具和仪器”应用中所述。这种分离亲本离子的技术倾向于沿着肽的主干切割肽，留下完整的侧链，因此它是对通常的碰撞诱导解离的重要补充，特别是对于修饰肽。我们实验室的第二个主要活动是非共价复合物的研究。我们研究这些重要结构的能力最近得到了改进，我们的实验室建造了一台专门为此目的设计的正交注射质谱仪。特别是，该仪器具有比我们之前的仪器高得多的加速电压（16kV vs 4kV），这保证了对典型非共价离子的灵敏度提高一个数量级。

The proposed research program aims to develop improved mass spectrometric methods for identifying and characterizing large biomolecules and biomolecular complexes. These methods will be applied to various biological problems using time-of-flight (TOF) mass spectrometers of innovative design, constructed in our own laboratory, or in cooperation with our research partner MDS Sciex.      The scientific approach exploits the advantages of TOF instruments for measuring masses, including effectively unlimited m/z range, rapid response, and high sensitivity. Our laboratory has both electrospray and MALDI (matrix-assisted laser desorption/ionization) ion sources coupled to TOF mass spectrometers; the two techniques often provide complementary information about biological molecules.      We plan to continue our extensive program of protein and peptide sequencing, using the hybrid QqTOF mass spectrometer (a cooperative design effort by Sciex and ourselves), which has a new target assembly that enables location of spots on a MALDI target under computer control with much higher speed and accuracy.  Such measurements normally follow the off-line chromatographic separation of complex biological mixtures.      We also plan to couple the recently-discovered electron capture method to a rejuvenated TOF instrument in our laboratory, as described in the accompanying "Research Tools and Instruments" application. This technique for dissociating parent ions tends to cleave peptides along their backbones, leaving the side chains intact, so it is an important complement to the usual collision-induced dissociation, particularly for modified peptides.      A second major activity in our laboratory has been the study of noncovalent complexes. Our ability to investigate these important structures has recently been improved by the construction in our laboratory of an orthogonal injection mass spectrometer specifically designed for the purpose. In particular, this instrument has much higher acceleration voltage than our previous one (16kV vs 4kV), which promises an order of magnitude increase in sensitivity for a typical noncovalent ion.