Fig 3. PlyPy can hydrolyze a Streptococcus pyogenes like peptidoglycan.
A non-labeled N-terminal acetylated peptide resembling the S. pyogenes peptidoglycan within the stem peptide and crossbridge (AEKAAA) was incubated with the S. pyogenes lysin PlyPy, and hydrolysis of the peptide was measured through mass spectrometry (MS). After incubation, an ion appeared at m/z 460.2404 which was matched as acetyl-AEKA (0.6 ppm). This interpretation was confirmed by tandem MS experiments. In the shown tandem MS, the precursor ion (p) as well as N-terminal (y) and C-terminal (b) fragment ions are marked. Fragment ions are matched with mass accuracies better than 2 ppm.
