Multiplex Substrate profiling of Pd-dinase, a dipeptidyl aminopeptidase secreted from a commensal bacterium
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ABSTRACT: Proteases within the C1B hydrolase family are encoded by many organisms. We subjected a putative C1B-like cysteine protease secreted by the human gut commensal Parabacteroidetes distasonis to mass spectrometry-based substrate profiling to find preferred peptide substrates. The P. distasonis protease, we termed Pd_dinase, has a sequential di-aminopeptidase activity with strong specificity for N-terminal glycine residues. The homohexameric Pd_dinase structure in complex with an irreversible dipeptide inhibitor, based on the preferred cleavage sequence, uncovered unexpected active site features that govern the strict substrate preferences and differentiate this protease from members of the C1B and broader papain-like C1 proteases. Due to their increased glycine content, we subjected several human-produced gut antimicrobial peptides to Pd_dinase and showed robust proteolytic degradation. We posit that secretion of Pd_dinase into the extracellular milieu and inactivation of host-produced antimicrobial peptides permits gut colonization by P. distasonis.
INSTRUMENT(S): Q Exactive
ORGANISM(S): Parabacteroides Distasonis (ncbitaxon:823)
SUBMITTER: Anthony O'Donoghue Dennis Wolan
PROVIDER: MSV000082228 | MassIVE | Sat Mar 31 18:53:00 BST 2018
REPOSITORIES: MassIVE
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