A software tool for the automated integration of accurate intact protein mass (AIPM) and bottom-up (BU) mass spectra searches/data in order to both confidently identify the intact proteins and to characterize their post-translational modifications (PTMs). The development of PTMSearchPlus was motivated by the desire to effectively integrate high-resolution intact protein molecular masses with bottom-up peptide MS/MS data. PTMSearchPlus requires as input both intact protein and proteolytic peptide mass spectra collected from the same protein mixture, a FASTA protein database, and a selection of possible PTMs, the types and ranges of which can be specified. The output of PTMSearchPlus is a list of intact and modified proteins matching the AIPM data concomitant with their respective peptides found by the BU search. This list also contains protein and peptide sequence coverage information, scores, etc. that can be used for further evaluation or refiltering of the results.
Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, Oak Ridge National Laboratory, TN, USA; Graduate School of Genome Science and Technology, University of Tennessee-Oak Ridge National Laboratory, TN, USA