MS1Connect: a mass spectrometry run similarity measure

Interpretation of newly acquired mass spectrometry data can be improved by identifying, from an online repos- itory, previous mass spectrometry runs that resemble the new data. However, this retrieval task requires comput- ing the similarity between an arbitrary pair of mass spectrometry runs. This is particularly challenging for runs acquired using different experimental protocols. We propose a method, MS1Connect, that calculates the simi- larity between a pair of runs by examining only the intact peptide (MS1) scans, and we show evidence that the MS1Connect score is accurate. Specifically, we show that MS1Connect outperforms several baseline methods on the task of predicting the species from which a given proteomics sample originated. In addition, we show that MS1Connect scores are highly correlated with similarities computed from fragment (MS2) scans, even though this data is not used by MS1Connect.