Condensed Aromatic Peptide Family of Microbial Metabolites, Inhibitors of CD28-CD80 Interactions

Abstract Three condensed aromatic peptides SCH79235 ( 1 ), SCH79236 ( 2 ), and SCH204698 ( 3 ) were isolated from the fermentation broth of a Streptomycete microorganism. The structure of SCH204698 ( 3 ) was established by extensive NMR spectral data. All these compounds exhibited good activity against CD28–CD80 binding with an IC 50 of 0.42, 0.38 and 0.22 μM, respectively.