Decision Tree Searching Strategy to Boost the Identification of Cross-Linked Peptides

We describe an efficient decision tree searching strategy (DTSS) to boost the identification of cross-linked peptides. The DTSS approach allows the identification of a wealth of complementary information to facilitate the construction of more protein–protein interaction networks for human cell lysate, which was tested by the use of a recently reported cross-linking data set (ACS Cent. Sci. 2019, 5, 1514–1522). A variant of the PhoX-linker, named pDSPE, was synthesized and applied to cross-link Escherichia coli cell lysate to demonstrate that the acquisition of doubly charged ions can significantly improve identification results. The method can be seamlessly integrated to other search engines to maximize the number of identified cross-links.