MRI: An Ultra High Resolution Mass Spectrometer to Identify Novel Protein Sequences and Modifications from Extinct Organisms Such as Tyrannosaurus Rex

获得已灭绝生物分子序列的能力将对物种进化的评估产生重大影响。来自已灭绝生物的古化石通常被降解，很少有有机物残留下来用于分子分析。我们正在开发一种非常敏感的方法，使用质谱法和生物信息学来提取和测序保存完好的骨骼中可用的蛋白质（主要是胶原蛋白）。对于6800万年前的化石，比如保存软组织的霸王龙化石，我们提取并测序了胶原蛋白的小片段，并获得了16万至60万年前乳齿象化石的重要序列信息。对于这样的标本，DNA不容易获得，蛋白质是唯一可测序的有机物质。这些序列是在低分辨率下获得的，因此许多等重水氨基酸和修饰氨基酸无法充分分辨。这项主要研究仪器（MRI）计划的拨款为获得ThermoScientific LTQ-Orbitrap质谱仪提供了部分支持，该质谱仪具有超高分辨率和质量精度，将使pi能够充分解析这些序列及其修改，而不会含糊不清，并以更高的灵敏度获取数百万年前化石的序列信息。最近发掘出许多保存良好的化石，这些化石将使用pi方法进行测序。这些序列将被用来评估它们与现代生物以及其他灭绝生物的进化关系。该仪器将被安置在贝斯以色列女执事医疗中心，33%的仪器时间将用于地面研究。北卡罗来纳州立大学从事脊椎动物和分子古生物学研究的学生将有机会接受这项最先进技术的培训。

The ability to obtain molecular sequence for extinct organisms will have a dramatic impact on the assessment of the evolution of species. Ancient fossils from extinct organisms are usually degraded and little organic material remains for molecular analysis. We are developing a very sensitive approach using mass spectrometry and bioinformatics for extracting and sequencing available protein (mainly collagen) that remains in well-preserved bones. For fossils as old as 68 million years such as a Tyrannosaurus rex preserving soft tissues, we have extracted and sequenced small fragments of collagen as well as acquired significant sequence information for a 160,000-600,000 year old mastodon fossil. For such specimens, DNA is not readily available and protein is the only sequenceable organic material. These sequences were acquired in low resolution so that many isobaric amino acids and modified amino acids could not be sufficiently resolved. Funding from this Major Research Instrumentation (MRI) Program grant provides partial support for the acquisition of a ThermoScientific LTQ-Orbitrap mass spectrometer capable of ultra high resolution and mass accuracy that will afford the PIs the ability to sufficiently resolve these sequences and their modifications without ambiguity and with greater sensitivity to acquire sequence information on fossils that are many millions of years old. Many fossils showing excellent preservation fossils have been recently excavated and these will be sequenced using the PIs approach. These sequences will then be used to assess their evolutionary relationships with modern organisms as well as other extinct organisms. The instrument will be housed at Beth Israel Deaconess Medical Center and 33% of the instrument time will be dedicated for terrestrial research. Students from North Carolina State University conducting research in vertebrate and molecular paleontology will be afforded the opportunity for training on this state-of-the-art technology.