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Updated: Jul 19, 2026

Structure-Guided Design and Development of Novel Cyclophilin A Inhibitors and Ganoderiol-F Derivatives: An In-Silico Approach
Published on: June 23, 2026
An RNA polymerase inhibitor, cyclothiazomycin B1, and its isomer
Masaru Hashimoto1, Takanori Murakami, Katsuyuki Funahashi
1Faculty of Agriculture and Life Science, Hirosaki University, 3-Bunkyo-cho, Hirosaki 036-8561, Japan. hmasaru@cc.hirosaki-u.ac.jp
Abstract:
Novel cyclic thiopeptides, cyclothiazomycins B1 (1) and B2 (2), were isolated from Streptomyces sp. A307 as potent hyphal swelling inducing substances. They are stable in the solid state but slowly isomerize with one another in solution. Degradation experiments and spectroscopic analyses disclosed that they comprise unique tricyclic structures each containing a dehydroalanine, and two dehydrohomoalanine residues, along with three thiazolines, three thiazoles, and a trisubstituted pyridine. Cyclothiazomycin B1 (1) is expected to be a powerful tool for DNA-RNA transcription studies, because this cyclopeptide inhibits DNA-dependent RNA synthesis by bacteriophage RNA polymerases.
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