THERMO COMPARISON BETWEEN LTQ AND VELOS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 在过去的十年中，通过液相色谱-电喷雾电离-串联质谱的高通量蛋白质组学分析的相当大的进展已经在很大程度上由仪器的不断改进而推动。高通量鉴定实验基于肽测序，并且主要通过使用串联质谱来完成，其中离子阱和基于阱的仪器已成为广泛采用的分析平台。为了满足日益苛刻的要求，深度的表征和吞吐量，我们提出了一种新开发的双压线性离子阱质谱仪（LTQ Velos），具有更高的灵敏度，提供了一个新的源设计，并证明实际的周期时间比LTQ XL短2倍，同时提高或保持MS/MS裂解光谱的光谱质量。与现有平台相比，这些改进导致从秀丽隐杆线虫复杂蛋白质组中检测和鉴定蛋白质和独特肽的大幅增加。进入质谱仪的大大增加的离子通量与低丰度前体离子的改进的分离相结合，导致低丰度肽的检测增加。与LTQ XL相比，这些改进累积导致对面包酵母（酿酒酵母）蛋白质组的显著更大渗透。另外，新仪器上更快的循环时间允许在给定深度的蛋白质组分析中获得更高的通量，使用LTQ Velos在60分钟内识别的肽和蛋白质比使用LTQ XL在180分钟内识别的肽和蛋白质更多。当进行质量分析时，分辨率超过25000半高宽（fwhm），就有可能同位素解析一个小的完整蛋白质及其片段，从而为自上而下的实验提供了可能性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The considerable progress in high-throughput proteomics analysis via liquid chromatography-electrospray ionization-tandem mass spectrometry over the past decade has been fueled to a large degree by continuous improvements in instrumentation. High-throughput identification experiments are based on peptide sequencing and are largely accomplished through the use of tandem mass spectrometry, with ion trap and trap-based instruments having become broadly adopted analytical platforms. To satisfy increasingly demanding requirements for depth of characterization and throughput, we present a newly developed dual-pressure linear ion trap mass spectrometer (LTQ Velos) that features increased sensitivity, afforded by a new source design, and demonstrates practical cycle times 2 times shorter than that of an LTQ XL, while improving or maintaining spectral quality for MS/MS fragmentation spectra. These improvements resulted in a substantial increase in the detection and identification of both proteins and unique peptides from the complex proteome of Caenorhabditis elegans, as compared to existing platforms. The greatly increased ion flux into the mass spectrometer in combination with improved isolation of low-abundance precursor ions resulted in increased detection of low-abundance peptides. These improvements cumulatively resulted in a substantially greater penetration into the baker's yeast (Saccharomyces cerevisiae) proteome compared to LTQ XL. Alternatively, faster cycle times on the new instrument allowed for higher throughput for a given depth of proteome analysis, with more peptides and proteins identified in 60 min using an LTQ Velos than in 180 min using an LTQ XL. When mass analysis was carried out with resolution in excess of 25 000 full width at half-maximum (fwhm), it became possible to isotopically resolve a small intact protein and its fragments, opening possibilities for top down experiments.