Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, S7N 5A9, Canada.
Proteome Sci. 2011 Oct 14;9 Suppl 1(Suppl 1):S3. doi: 10.1186/1477-5956-9-S1-S3.
Charge states of tandem mass spectra from low-resolution collision induced dissociation can not be determined by mass spectrometry. As a result, such spectra with multiple charges are usually searched multiple times by assuming each possible charge state. Not only does this strategy increase the overall database search time, but also yields more false positives. Hence, it is advantageous to determine charge states of such spectra before database search.
We propose a new approach capable of determining the charge states of low-resolution tandem mass spectra. Four novel and discriminant features are introduced to describe tandem mass spectra and used in Gaussian mixture model to distinguish doubly and triply charged peptides. By testing on three independent datasets with known validity, the results have shown that this method can assign charge states to low-resolution tandem mass spectra more accurately than existing methods.
The proposed method can be used to improve the speed and reliability of peptide identification.
来自低分辨碰撞诱导解离的串联质谱的电荷状态不能通过质谱来确定。结果，这种具有多个电荷的光谱通常会通过假设每个可能的电荷状态多次进行搜索。这种策略不仅增加了总体数据库搜索时间，而且还产生了更多的假阳性。因此，在数据库搜索之前确定这种光谱的电荷状态是有利的。
我们提出了一种能够确定低分辨率串联质谱电荷状态的新方法。引入了四个新颖而有区别的特征来描述串联质谱，并将其用于高斯混合模型中，以区分双电荷和三电荷肽。通过对三个具有已知有效性的独立数据集进行测试，结果表明，该方法比现有方法能够更准确地分配低分辨率串联质谱的电荷状态。
该方法可用于提高肽鉴定的速度和可靠性。
