资 源 简 介
Electron-transfer dissociation (ETD) induces fragmentation along the peptide backbone by transferring an electron from a radical anion to a protonated peptide. ETD has a unique characteristic, as contrasted with collision induced dissociation, of side chains and modifications such as phosphorylation being left intact through the dissociation process. Since the precursor charge state is an important input to MS/MS sequence database search tools, the ability to accurately determine the precursor charge is helpful for the identification process. And as ETD can be applied to larger peptides that can be highly charged, the need for accurate precursor charge state determination is magnified in order to reduce having to search a large range of all possible precursor charge states. To address this problem, we have developed an ETD charge state prediction tool based on support vector machine classifiers. This tool is written in Java and makes use of the LIBSVM (http://www.csie.ntu.edu.tw/~cj
