biostudies-literatureAllyjaun SInnovate UKBarbour FoundationMedical Research Council21144-21155https://www.ebi.ac.uk/biostudies/studies/S-EPMC12557396biostudies-literatureUnknown68(20)The lipopolysaccharide (LPS) transport (Lpt) system in Gram-negative bacteria maintains the integrity of the asymmetric bacterial outer membrane (OM). LPS biogenesis systems are essential in most Gram-negative bacteria, with LptDE responsible for the delivery of LPS to the outer leaflet of the OM. As an externally accessible, essential protein, LptDE offers a promising target for inhibitor development without the need for cellular penetration. However, there are no direct inhibitors of <i>E. coli</i> LptDE, and drug discovery is made challenging since it is a membrane target without a conventional active site. Here, the bicycle phage display platform was used in combination with cryogenic-electron microscopy (cryo-EM) and surface plasmon resonance to identify and map bicyclic peptide bindeJournal of medicinal chemistryHigh-Throughput Identification and Characterization of LptDE-Binding Bicycle Peptides Using Phage Display and Cryo-EM.PMC12557396328081U-01627510086683MR/X50290X/1Cooper LParis GHubbard Jvan den Berg BLewis NDunbar EHolding FArruda Bezerra GSt Denis MANewman HBournakas NChirgadze DYBrown PSkynner MJHardwick SWDawson MJBeswick PPellegrino SNewell SRowland CEAllyjaun SfalseHigh-Throughput Identification and Characterization of LptDE-Binding Bicycle Peptides Using Phage Display and Cryo-EM.The lipopolysaccharide (LPS) transport (Lpt) system in Gram-negative bacteria maintains the integrity of the asymmetric bacterial outer membrane (OM). LPS biogenesis systems are essential in most Gram-negative bacteria, with LptDE responsible for the delivery of LPS to the outer leaflet of the OM. As an externally accessible, essential protein, LptDE offers a promising target for inhibitor development without the need for cellular penetration. However, there are no direct inhibitors of <i>E. coli</i> LptDE, and drug discovery is made challenging since it is a membrane target without a conventional active site. Here, the bicycle phage display platform was used in combination with cryogenic-electron microscopy (cryo-EM) and surface plasmon resonance to identify and map bicyclic peptide binde2025-01-01T00:00:00Z2025 Oct2026-06-05T06:41:13.436Z2026-06-05T03:06:43.779ZS-EPMC125573964104801610.1021/acs.jmedchem.5c00307