Synthesis, Structure-Activity Relationship Study, Bioactivity, and Nephrotoxicity Evaluation of the Proposed Structure of the Cyclic Lipodepsipeptide Brevicidine B.

The brevicidines represent a novel class of nonribosomal antimicrobial peptides that possess remarkable potency and selectivity toward highly problematic and resistant Gram-negative pathogenic bacteria. A recently discovered member of the brevicidine family, coined brevicidine B (), comprises a single amino acid substitution (from d-Tyr to d-Phe) in the amino acid sequence of the linear moiety of brevicidine () and was reported to exhibit broader antimicrobial activity against both Gram-negative (MIC = 2-4 μgmL) and Gram-positive (MIC = 2-8 μgmL) pathogens. Encouraged by this, we herein report the first total synthesis of the proposed structure of brevicidine B (), building on our previously reported synthetic strategy to access brevicidine ().

Towards a High-Affinity Peptidomimetic Targeting Proliferating Cell Nuclear Antigen from .

Invasive fungal infections (IFIs) are prevalent in immunocompromised patients. Due to alarming levels of increasing resistance in clinical settings, new drugs targeting the major fungal pathogen are required. Attractive drug targets are those involved in essential processes like DNA replication, such as proliferating cell nuclear antigens (PCNAs).

Designing Fluorescent Nuclear Permeable Peptidomimetics to Target Proliferating Cell Nuclear Antigen.

Human proliferating cell nuclear antigen (PCNA) is a critical mediator of DNA replication and repair, acting as a docking platform for replication proteins. Disrupting these interactions with a peptidomimetic agent presents as a promising avenue to limit proliferation of cancerous cells. Here, a p21-derived peptide was employed as a starting scaffold to design a modular peptidomimetic that interacts with PCNA and is cellular and nuclear permeable.

PPARγ Corepression Involves Alternate Ligand Conformation and Inflation of H12 Ensembles.

Inverse agonists of peroxisome proliferator activated receptor γ (PPARγ) have emerged as safer alternatives to full agonists for their reduced side effects while still maintaining impressive insulin-sensitizing properties. To shed light on their molecular mechanism, we characterized the interaction of the PPARγ ligand binding domain with SR10221. X-ray crystallography revealed a novel binding mode of SR10221 in the presence of a transcriptionally repressing corepressor peptide, resulting in much greater destabilization of the activation helix, H12, than without corepressor peptide.

Factors influencing on-resin depsipeptide bond formation: case studies on daptomycin- and brevicidine-derived sequences.

Depsipeptides are an important class of bioactive natural products, where a growing number of genome-mined structures that display anti-microbial activity are macrocyclic depsipeptides. Chemically, peptide ester (depsipeptide) bond formation often displays low yields, and thereby hampers efforts to access these structures for structure-activity studies. Herein, we present a systematic study of the variables that influence depsipeptide bond formation on-resin, using simplified sequences derived from antibiotic peptides, daptomycin and brevicidine, prepared Fmoc-based solid-phase synthesis.