IDBR: A New Mass Spectrometer for the Detection and collection of Biomolecules Of High Molecular Mass

Indiana University, Bloomington IN

Investigators

Abstract

Mass spectrometry (MS) is an indispensible tool of the modern biologist. The application of MS techniques in the biological sciences has provided significant new capabilities and analyses with previously unknown levels of sensitivity, specificity, and selectivity, yielding new insight into intricate biological problems. The aim of this research project is the development a new type of mass spectrometer for biological research that is capable of analyzing and collecting ions of very high molecular mass. Specifically, a distance-of-flight mass spectrometer (DOFMS) will be designed and constructed that separates ions of differing mass-to-charge (m/z) ratio based upon the distance each travels during a given time period, ultimately spatially segregating the ions along a surface. This physical distribution of ions according to m/z is then measured by using a novel position-selective and charge-sensitive ion detector that has already been developed in the PIs? laboratory. In contrast to extant methods, this strategy exhibits no upper mass limit either in the means of mass separation or in the mechanism of the ion detection, making the entire mass range available for analysis. The physical separation of the ions also permits the ions to be collected upon a specialized secondary surface in a technique known as soft-landing mass spectrometry. Somewhat surprisingly, when the collected, neutralized ions are subsequently removed from vacuum they often retain their biological efficacy and are available for analysis by other biochemical or analytical techniques. The DOFMS will advance the biological sciences by providing new and significantly improved MS capabilities to the biologist. The unlimited mass range of the instrument will be exploited by studying massive biopolymers and aggregates of biological interest such as viruses, enzyme-substrate complexes, phages, protein complexes, and epitope complexes. From the distribution of molecular masses, biologists will learn directly about the distribution of individuals that comprises the biological population under study, as well as important insights about associative binding and the effects of mutagenic variation. Moreover, these species will be detected with the sensitivity, accuracy, and specificity of MS, then collected for subsequent analysis or amplification via biochemical or alternative means. In this way the results of MS study can be directly compared to results of other analyses, further improving information content. This project meets an emerging need within the biological community for rapid, sensitive analysis of biological species of high molecular weight and complexity. The broader impacts of the proposed program come in several forms. Both graduate and undergraduate students have been involved in the initial studies and will continue to participate in both instrument development and application. Special efforts are made to include underrepresented groups; indeed, portions of the preliminary work have been performed by a female graduate student and a graduate student of African-American descent. Because the proposed studies are inherently multidisciplinary, collaboration with investigators in the biological sciences is important to success. Such relationships have been formed around biological questions of significance, and their collaborative involvement will both address important biological questions and refine the new instrument. Also, a plan has already been established to make this new tool available to the broader biology community, in part through the collaborations mentioned above but also through commercial development and through an existing Federal user facility. Overall, the successful deployment of this new analytical tool will have a broader impact of its own, and leveraging the significant strengths of MS to the study of complex and large biological entities will yield new knowledge that cannot be gained by other means.