Quorum sensing (QS) is a cell–cell communication mechanism that enables bacteria to assess their population density and alter their behavior upon reaching high cell number. Many bacterial pathogens utilize QS to initiate an attack on their host, thus QS has attracted significant attention as a potential antivirulence alternative to traditional antibiotics. Streptococcus pneumoniae, a notorious human pathogen responsible for a variety of acute and chronic infections, utilizes the competence regulon and its associated signaling peptide, the competence stimulating peptide (CSP), to acquire antibiotic resistance and establish an infection. In this work, we sought to define the binding pockets within the ComD1 receptor used for binding the hydrophobic side-chain residues in CSP1 through the introduction of highly-conservative point mutations within the peptide. Optimization of these binding interactions could lead to the development of highly potent CSP-based QS modulators while the inclusion of non-natural amino acids within the CSP sequence would confer resistance to protease degradation, a requirement for drug candidates.

Thiourea catalysts accelerate aminolysis of N-acyl homoserine lactones (AHLs), molecules integral to bacterial quorum sensing. The catalysts afford rate enhancement of up to 10 times the control in CD(3)CN. Mild catalysis in other polar aprotic solvents is still observed, while the activity is attenuated in polar protic solvents.

Anomalous protein-protein interactions (PPIs) have been correlated to a variety of disease states, such as cancer, infectious disease, neurological disorders, diabetes, endocrine disorders and cardiovascular disease. Stapled peptides are an emerging intervention for these PPIs due to their improved structural rigidity and pharmacokinetic properties relative to unstapled peptides. This review details the most recent advances in the field of stapled peptide therapeutics, including the increasing variety of PPIs being targeted and types of peptide staples being employed.

Streptococcus pneumoniae (pneumococcus) is a human pathobiont that causes drastic antibiotic‐resistant infections and is responsible for millions of deaths universally. Pneumococcus pathogenicity relies on the competence‐stimulating peptide (CSP)‐mediated quorum‐sensing (QS) pathway that controls competence development for genetic transformation and, consequently, the spread of antibiotic resistance and virulence genes. Modulation of QS in S. pneumoniae can therefore be used to enervate pneumococcal infectivity as well as minimize the susceptibility to resistance development. In this work, we sought to optimize the interaction of CSP1 with its cognate transmembrane histidine kinase receptor (ComD1) through substitution of proteogenic and nonproteogenic amino acids on the hydrophobic binding face of CSP1. The findings from this study not only provided additional structure–activity data that are significant in optimizing CSP1 potency, but also led to the development of potent QS modulators. These CSP‐based QS modulators could be used as privileged scaffolds for the development of antimicrobial agents against pneumococcal infections.

The prompt appearance of multiantibiotic-resistant bacteria necessitates finding alternative treatments that can attenuate bacterial infections while minimizing the rate of antibiotic resistance development. Streptococcus pneumoniae, a notorious human pathogen, is...