Palmblad Magnus, Bindschedler Laurence V, Gibson Trevor M, Cramer Rainer
The BioCentre, The University of Reading, Reading, UK.
Rapid Commun Mass Spectrom. 2006;20(20):3076-80. doi: 10.1002/rcm.2707.
Accurately measured peptide masses can be used for large-scale protein identification from bacterial whole-cell digests as an alternative to tandem mass spectrometry (MS/MS) provided mass measurement errors of a few parts-per-million (ppm) are obtained. Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS) routinely achieves such mass accuracy either with internal calibration or by regulating the charge in the analyzer cell. We have developed a novel and automated method for internal calibration of liquid chromatography (LC)/FTICR data from whole-cell digests using peptides in the sample identified by concurrent MS/MS together with ambient polydimethylcyclosiloxanes as internal calibrants in the mass spectra. The method reduced mass measurement error from 4.3 +/- 3.7 ppm to 0.3 +/- 2.3 ppm in an E. coli LC/FTICR dataset of 1000 MS and MS/MS spectra and is applicable to all analyses of complex protein digests by FTICRMS.
如果能获得百万分之几（ppm）的质量测量误差，那么精确测量的肽质量可用于从细菌全细胞消化物中大规模鉴定蛋白质，作为串联质谱（MS/MS）的替代方法。傅里叶变换离子回旋共振（FTICR）质谱（MS）通常通过内部校准或调节分析器单元中的电荷来实现这种质量精度。我们开发了一种新颖的自动化方法，用于对来自全细胞消化物的液相色谱（LC）/FTICR数据进行内部校准，该方法使用通过同时进行的MS/MS鉴定的样品中的肽以及作为质谱内标物的环境聚二甲基环硅氧烷。在一个包含1000个MS和MS/MS光谱的大肠杆菌LC/FTICR数据集中，该方法将质量测量误差从4.3±3.7 ppm降低到了0.3±2.3 ppm，并且适用于FTICRMS对复杂蛋白质消化物的所有分析。
