FIGURE 5.

Limited proteolysis and mass spectrometry identified the minimal binding site for PulS. A, 50 μm Sdom, 50 μm PulS, or an equimolar complex was digested with 30, 15, or 7.5 nm thermolysin and peptide fragments were separated by SDS-PAGE. Arrows indicate the additional bands found upon proteolysis of the Sdom sample but not detected after proteolysis of the complex. B, schematic representation of the most relevant peptide fragments identified by mass spectrometry (see supplemental Table S2 for list of total peptides identified), including amino acid coordinates and listed in descending order from the peptide with the highest relative intensity. Top, amino acid sequence and numbering of the Sdom (His tag not included), asterisk indicates the common cleavage event between both samples.