title: An RNA polymerase inhibitor, cyclothiazomycin B1, and its isomer.
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.
authors.affiliation: Faculty of Agriculture and Life Science, Hirosaki University, 3-Bunkyo-cho, Hirosaki 036-8561, Japan. hmasaru@cc.hirosaki-u.ac.jp
authors.forename: Masaru
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Takanori
authors.initials: T
authors.lastname: Murakami
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Funahashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Tokunaga
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Nihei
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Okuno
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Kimura
authors.forename: Hideo
authors.initials: H
authors.lastname: Naoki
authors.forename: Hyouta
authors.initials: H
authors.lastname: Himeno
mesh_terms: D002851:Chromatography, High Pressure Liquid; D012321:DNA-Directed RNA Polymerases / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D005285:Fermentation; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D013302:Streptomyces / Q000145:classification / Q000378:metabolism; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000092502:Renin Inhibitors
chemical_list: D012321:DNA-Directed RNA Polymerases; D004791:Enzyme Inhibitors; D010455:Peptides; D010456:Peptides, Cyclic; D013844:Thiazoles; D000092502:Renin Inhibitors; C569101:cyclothiazomycin B1; C069913:cyclothiazomycin