Mass spectra alignments and their significance

Mass Spectrometry has become one of the most popular analysis techniques in Genomics and Systems Biology. We investigate a general framework that allows the alignment (or matching) of any two mass spectra. In particular, we examine the alignment of a reference mass spectrum generated in silico from a database, with a measured sample mass spectrum. In this context, we assess the significance of alignment scores for character-specific cleavage experiments, such as tryptic digestion of amino acids. We present an efficient approach to estimate this significance, with runtime linear in the number of detected peaks. In this context, we investigate the probability that a random string over a weighted alphabet contains a substring of some given weight.