Purchase of a Linear Ion Trap/Fourier Transform Mass Spectrometer

描述（由申请人提供）： 该提案要求为Thermoelectron（桑尼维尔，CA）型号LTQ FT 22000混合线性离子阱/傅里叶变换质谱仪提供资金，该质谱仪配备有电喷雾电离（ESI）源、红外多光子解离（IRMPD）和电子捕获解离（ECD）。该仪器将直接使一组主要用户受益，他们都有NIH的研究支持，目前都在研究中使用质谱仪。许多研究人员是一个或多个NIH支持的路线图和计划赠款的参与者，这些资助将质谱分析作为研究工作的一个组成部分，并为扩大从这些资源中受益的研究人员的数量提供了一种手段。这包括约翰霍普金斯缺血和缺氧蛋白质组学中心（N 01 HV 28180，由NHLBI支持）和约翰霍普金斯赖氨酸修饰网络和途径技术中心（TCNP U 54 RR 020839，由NIH支持）。该仪器的所有特点和能力都将得到利用，这些特点和能力使它有别于约翰霍普金斯大学现有仪器的特点和能力。在赖氨酸修饰和组蛋白结构的研究中，高质量分辨率（50，000到100，000）将区分三甲基和乙酰化位点（可能存在于不同分子的同一位点）。ECD和IRMPD将用于片段化由SUMO化产生的非常大的分支肽结构，以及绘制组蛋白和组蛋白转移酶中的多乙酰化赖氨酸所需的非常大的部分消化的肽片段。ECD对于碳水化合物、O-连接糖肽和带负电荷的翻译后修饰（主要是磷酸化）的结构分析也至关重要。这里的许多研究是蛋白质组学研究，利用蛋白质数据库从其消化的肽中识别复杂混合物中的蛋白质（以及它们的PTM）。高质量精度（1-5 ppm）是提供正确鉴定的关键。该仪器将设在中大西洋质谱实验室并由其管理，由代表主要用户和合作者的四名个人操作。

DESCRIPTION (provided by applicant): This proposal requests funds for a Thermoelectron (Sunnyvale, CA) model LTQ FT22000 hybrid linear ion trap/Fourier transform mass spectrometer, equipped with an electrospray ionization (ESI) source, infrared multiphoton dissociation (IRMPD) and electron capture dissociation (ECD). The instrument would directly benefit a group of major users all of whom have NIH research support and all of whom currently use mass spectrometry in their research. Many of the investigators are participants in one or more NIH-supported roadmap and program project grants, which incorporate mass spectrometric analysis as an integral part of the research effort and provide a means for expanding the number of investigators benefiting from these resources. This includes the Johns Hopkins Center for Proteomics of Ischemia and Hypoxia (N01 HV28180, supported by NHLBI) and the Johns Hopkins Technology Center for Networks and Pathways of Lysine Modifications (TCNP U54 RR020839, supported by NIH). All of the features and capabilities of this instrument, which distinguish it from those available on current instruments at Johns Hopkins, will be utilized. In work by several investigators on lysine modifications and the structures of histones, high mass resolution (50,000 to 100,000) will distinguish trimethyl and acetylation sites (which may exist at the same site on different molecules). ECD and IRMPD will be used to fragment the very large branched peptide structures resulting from SUMOylation, as well as very large, partially digested peptide fragments needed to map polyacetylated lysines in histones and histone transferases. ECD will also be critical for the structural analysis of carbohydrates, O-linked glycopeptides and negatively charged post- translational modifications, primarily phosphorylation. Many of the studies here are proteomics studies, utilizing protein databases for identification of proteins in complex mixtures (as well as their PTMs) from their digested peptides. High mass accuracy (1-5 ppm) is key to providing correct identifications. The instrument will be housed in and managed by the Middle Atlantic Mass Spectrometry Laboratory and operated by four individuals representing the Major Users and collaborators.