TY - JOUR

T1 - Proteolytic activity of Escherichia coli oligopeptidase B against proline-rich antimicrobial peptides

AU - Mattiuzzo, Maura

AU - De Gobba, Cristian

AU - Runti, Giulia

AU - Mardirossian, Mario

AU - Bandiera, Antonella

AU - Gennaro, Renato

AU - Scocchi, Marco

PY - 2014

Y1 - 2014

N2 - Oligopeptidase B (OpdB) is a serine peptidase widespread among bacteria and protozoa that has emerged as a virulence factor despite its function has not yet been precisely established. By using an OpdB-overexpressing Escherichia coli strain, we found that the overexpressed peptidase makes the bacterial cells specifically less susceptible to several proline-rich antimicrobial peptides known to penetrate into the bacterial cytosol, and that its level of activity directly correlates with the degree of resistance. We established that E. coli OpdB can efficiently hydrolyze in vitro cationic antimicrobial peptides up to 30 residues in length, even though they contained several prolines, shortening them to inactive fragments. Two consecutive basic residues are a preferred cleavage site for the peptidase. In the case of a single basic residue, there is no cleavage if proline residues are present in the P1 and P2 positions. These results also indicate that cytosolic peptidases may cause resistance to antimicrobial peptides that have an intracellular mechanism of action, such as the proline-rich peptides, and may contribute to define the substrate specificity of the E. coli OpdB.

AB - Oligopeptidase B (OpdB) is a serine peptidase widespread among bacteria and protozoa that has emerged as a virulence factor despite its function has not yet been precisely established. By using an OpdB-overexpressing Escherichia coli strain, we found that the overexpressed peptidase makes the bacterial cells specifically less susceptible to several proline-rich antimicrobial peptides known to penetrate into the bacterial cytosol, and that its level of activity directly correlates with the degree of resistance. We established that E. coli OpdB can efficiently hydrolyze in vitro cationic antimicrobial peptides up to 30 residues in length, even though they contained several prolines, shortening them to inactive fragments. Two consecutive basic residues are a preferred cleavage site for the peptidase. In the case of a single basic residue, there is no cleavage if proline residues are present in the P1 and P2 positions. These results also indicate that cytosolic peptidases may cause resistance to antimicrobial peptides that have an intracellular mechanism of action, such as the proline-rich peptides, and may contribute to define the substrate specificity of the E. coli OpdB.

KW - Antimicrobial peptide

KW - proline-rich

KW - oligopeptidase B

KW - proteolysis

U2 - 10.4014/jmb.1310.10015

DO - 10.4014/jmb.1310.10015

M3 - Journal article

VL - 24

SP - 160

EP - 167

JO - Microbiology and Biotechnology Letters

JF - Microbiology and Biotechnology Letters

SN - 1598-642X

IS - 2

ER -