identification of lipid II binding lipopeptides with antibacterial activity against vancomycin-resistant bacteria.

Creative strategies for identifying new antibiotics are essential to addressing the looming threat of a post-antibiotic era. We here report the use of a targeted peptide phage display screen as a means of generating novel antimicrobial lipopeptides. Specifically, a library of phage displayed bicyclic peptides was screened against a biomolecular target based on the bacterial cell wall precursor lipid II.

Development of Potent and Selective S. aureus Sortase A Inhibitors Based on Peptide Macrocycles.

Sortases are transpeptidase enzymes that anchor surface proteins, including virulence factors, to the cell wall of Gram-positive bacteria, and they are potential targets for the development of anti-infective agents. While several large compound libraries were searched by high-throughput screening, no high-affinity inhibitors of sortases could be developed to date. Here, we applied phage display to screen billions of peptide macrocycles against sortase A (SrtA) of Staphylococcus aureus (S.

Identification of target-binding peptide motifs by high-throughput sequencing of phage-selected peptides.

High-throughput sequencing was previously applied to phage-selected peptides in order to gain insight into the abundance and diversity of isolated peptides. Herein we developed a procedure to efficiently compare the sequences of large numbers of phage-selected peptides for the purpose of identifying target-binding peptide motifs. We applied the procedure to analyze bicyclic peptides isolated against five different protein targets: sortase A, urokinase-type plasminogen activator, coagulation factor XII, plasma kallikrein and streptavidin.

Phage selection of photoswitchable peptide ligands.

Photoswitchable ligands are powerful tools to control biological processes at high spatial and temporal resolution. Unfortunately, such ligands exist only for a limited number of proteins and their development by rational design is not trivial. We have developed an in vitro evolution strategy to generate light-activatable peptide ligands to targets of choice.

Bicyclic peptide ligands pulled out of cysteine-rich peptide libraries.

Bicyclic peptide ligands were found to have good binding affinity and target specificity. However, the method applied to generate bicyclic ligands based on phage-peptide alkylation is technically complex and limits its application to specialized laboratories. Herein, we report a method that involves a simpler and more robust procedure that additionally allows screening of structurally more diverse bicyclic peptide libraries.

Phage selection of bicyclic peptides.

Bicyclic peptides are small, constrained peptides that can bind with high affinity and selectivity to protein targets. Their small size provides a number of advantages over larger protein-based ligands, including access to chemical synthesis, better tissue penetration, and a wider choice of application routes. Bicyclic peptide ligands can be identified using phage display technology with moderate effort and cost.

Boosting the sensitivity of ligand-protein screening by NMR of long-lived states.

A new NMR method for the study of ligand-protein interactions exploits the unusual lifetimes of long-lived states (LLSs). The new method provides better contrast between bound and free ligands and requires a protein-ligand ratio ca. 25 times lower than for established T(1ρ) methods, thus saving on costly proteins.