MASS SPECTROMETER

这是对飞行时间（TOF）质谱仪的请求。该仪器将在索尔克研究所的许多研究人员和其他学术机构的研究人员的研究项目中发挥关键作用（见支持信）。我们将获得有关新型激素、毒素和生长因子的准确质量和结构信息，并描述已知一级结构分子中翻译后修饰的位置和性质。已经确定了一个由10名调查人员组成的小组，他们的研究依赖于只有使用所要求的仪器才能进行的分析。仪器的灵敏度对我们目前尝试表征新肽和蛋白质至关重要。在各种不稳定肽上获得的结果表明，与连续提取和目前可用的更基本的分析相比，脉冲离子提取和所要求的仪器上的激光光学增加了灵敏度。该仪器对于确定磷酸化蛋白的位点也至关重要，因为磷酸化水平低或引入放射性示踪剂的有害影响禁止常规电泳和放射性化学测序方案。通过分析水解的磷酸化蛋白，我们将提高完整质量分析的灵敏度，同时使用全自动前体选择和PSD将允许对磷酸化肽进行快速MS2分析，以帮助在肽中存在多个潜在磷酸化位点时确定磷酸化位点。升级后的仪器的质量精度和分辨率对于鉴定由“未知”蛋白质产生的水解片段非常有价值。该仪器将适用于在进行还原之前和之后测量肽的拟议方法，从而能够对含二硫桥的肽进行PSD分析。索尔克研究所已经提供的其他仪器包括双聚焦磁扇形质谱仪，具有液体二次电离和激光解吸电离源，电喷雾离子阱质谱仪和带PTH分析仪的气相测序仪。需要升级TOF质谱仪来补充Salk研究所强大的经典Edman测序方法。该仪器将位于MS设施。一项重大的机构承诺将确保这一工具由受过培训的人员操作和维护。所有的测量都将在克雷格的监督下进行。

This is a request for a time-of-flight (TOF) mass spectrometer. The instrument will play a pivotal role in the research projects of many investigators at the Salk Institute and researchers at other academic institutions (see letters of support). We will obtain accurate mass and structural information on novel hormones, toxins, and growth factors and characterize the sites and nature of post-translational modifications in molecules of known primary structure. A group of 10 investigators has been identified whose research is dependent on analyses only possible with the requested instrument. The sensitivity of the instrument is essential to our current attempts to characterize novel peptides and proteins. Results obtained on a variety of unstable peptides illustrate the increased sensitivity available with pulsed ion extraction and the laser optics on the requested instrument compared with continuous extraction and the more rudimentary analysis currently available. The instrument will also be vital for identifying the site of phosphorylation in phosphoproteins where either the low level of phosphorylation or the deleterious effects of introducing a radioactive tracer prohibit conventional electrophoresis and radioactive chemical sequencing protocols. By analyzing the hydrolyzed phosphoprotein, we will increase the sensitivity of intact mass analysis while the use of fully automated precursor selection and PSD will allow rapid MS2 analysis of the phosphopeptide to help identify the site of phosphorylation when more than one potential site of phosphorylation exists in the peptide. The mass accuracy and resolution available with the upgraded instrument will be extremely valuable for the identification of hydrolysis fragments generated from 'unknown' proteins. The instrument will be amenable to a proposed approach of measuring a peptide both prior to and after carrying out reduction and thereby enabling PSD analysis of disulfide bridge-containing peptides. Other instruments already available at the Salk Institute include a double focusing magnetic sector mass spectrometer with both liquid secondary ionization and laser desorption ionization sources, an electrospray ion trap mass spectrometer, and gas phase sequencers with PTH analyzers. The requested upgraded TOF mass spectrometer is needed to complement the strong classical Edman sequencing approach at the Salk Institute. The instrument will be located in the MS Facility. A significant institutional commitment will ensure that this instrument is operated and maintained by trained personnel. All measurements will be made under the supervision of A. Craig.