Determinants of maturation of the Staphylococcus aureus autoinducing peptide

作者：Liwei Fang, Chance J. Cosgriff, Francis Alonzo · 发表于：Journal of Bacteriology · 年份：2024 · DOI：10.1128/jb.00195-24 · 被引用次数：6 · 研究领域：Antimicrobial Resistance in Staphylococcus、Biochemical and Structural Characterization、Bacterial biofilms and quorum sensing

ABSTRACT The a ccessory g ene r egulatory (Agr) system is required for virulence factor gene expression and pathogenesis of Staphylococcus aureus . The Agr system is activated in response to the accumulation of a cyclic autoinducing peptide (AIP), which is matured and secreted by the bacterium. The precursor of AIP, AgrD, consists of the AIP flanked by an N-terminal α -helical Leader and a charged C-terminal tail. AgrD is matured to AIP by the action of two proteases, AgrB and MroQ. AgrB cleaves the C-terminal tail and promotes the formation of a thiolactone ring, whereas MroQ cleaves the N-terminal Leader in a manner that depends on the four-amino acid linker immediately following a conserved IG helix breaker motif. However, the attributes of AgrD that dictate the sequence of events in peptide maturation are not fully defined. Here, we used engineered AgrD peptide intermediates to ascertain the sufficiency of MroQ for N-terminal peptide cleavage, peptide export, and generation of mature AIP. We found that MroQ promotes the removal of the N-terminal Leader peptide from both linear and cyclic peptide intermediates, while peptide cyclization remained essential for signaling. The expression of the Leader peptide in isolation was sufficient for MroQ-dependent cleavage proximal to the four-amino-acid linker. In addition, active site mutations within AgrB destabilized full-length AgrD and thiolactone-containing intermediates and prevented the release of the Leader peptide. Al...