CROSS-CORRELATION ALGORITHM FOR CALCULATION OF PEPTIDE MOLECULAR WEIGHT FROM TA

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。我们开发了一种方法，利用互相关函数直接从相应的串联质谱图中确定多肽离子的分子量。我们已经证明，从复杂蛋白质混合物的胰酶消化液中鉴定出的串联质谱图的~90%可以计算出单同位素分子量。计算的单同位素质量的准确性取决于分析光谱的分辨率和质量精度，但对于线性离子陷阱质谱图，通常为-lt；0.25amu。为低分辨率离子陷阱数据计算准确的单同位素分子量的能力应该会显著提高数据库搜索的速度和性能，数据库搜索采用的典型质量精度为~3amu。此外，这一策略还可以用于识别在数据无关的碰撞激活解离中使用大离子选择窗口获得的串联质谱图的前体离子，并且具有识别多路复用串联质量sp.的潜力

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. We have developed an approach to identify the molecular weight of a peptide ion directly from its corresponding tandem mass spectrum using a cross-correlation function. We have shown that the monoisotopic molecular weight can be calculated for ~90% of tandem mass spectra identified from tryptic digests of complex protein mixtures. The accuracy of the calculated monoisotopic masses was dependent on the resolution and mass accuracy of the spectra analyzed, but was typically <0.25 amu for linear ion trap mass spectra. The ability to calculate accurate monoisotopic molecular weights for low-resolution ion trap data should significantly improve both the speed and performance of database searches for which typical mass accuracies of ~3 amu are employed. In addition, this strategy can also be used to identify the precursor ion for tandem mass spectra acquired using large ion selection windows in data-independent collision-activated dissociation and has the potential to identify multiplexed tandem mass sp