biostudies-literatureUnknown7(1)Berry IJProteolytic processing alters protein function. Here we present the first systems-wide analysis of endoproteolysis in the genome-reduced pathogen Mycoplasma hyopneumoniae. 669 N-terminal peptides from 164 proteins were identified, demonstrating that functionally diverse proteins are processed, more than half of which 75 (53%) were accessible on the cell surface. Multiple cleavage sites were characterised, but cleavage with arginine in P1 predominated. Putative functions for a subset of cleaved fragments were assigned by affinity chromatography using heparin, actin, plasminogen and fibronectin as bait. Binding affinity was correlated with the number of cleavages in a protein, indicating that novel binding motifs are exposed, and protein disorder increases, after a cleavage event. GlyceraldeScientific reports11063https://www.ebi.ac.uk/biostudies/studies/S-EPMC5593965biostudies-literatureN-terminomics identifies widespread endoproteolysis and novel methionine excision in a genome-reduced bacterial pathogen.PMC5593965Berry IJRaymond BBAPadula MPWidjaja MDjordjevic SPJarocki VMTacchi JLfalseN-terminomics identifies widespread endoproteolysis and novel methionine excision in a genome-reduced bacterial pathogen.Proteolytic processing alters protein function. Here we present the first systems-wide analysis of endoproteolysis in the genome-reduced pathogen Mycoplasma hyopneumoniae. 669 N-terminal peptides from 164 proteins were identified, demonstrating that functionally diverse proteins are processed, more than half of which 75 (53%) were accessible on the cell surface. Multiple cleavage sites were characterised, but cleavage with arginine in P1 predominated. Putative functions for a subset of cleaved fragments were assigned by affinity chromatography using heparin, actin, plasminogen and fibronectin as bait. Binding affinity was correlated with the number of cleavages in a protein, indicating that novel binding motifs are exposed, and protein disorder increases, after a cleavage event. Glyceralde2017-01-01T00:00:00Z2017 Sep2026-05-01T08:03:58.765Z2025-05-29T21:55:49.833ZS-EPMC55939652889415410.1038/s41598-017-11296-9