|
| Section2 = | Section3 = }} Kasugamycin (Ksg) is an aminoglycoside antibiotic that was originally isolated in 1965, from ''Streptomyces kasugaensis'', a ''Streptomyces'' strain found near the Kasuga shrine in Nara, Japan. Kasugamycin was discovered by Hamao Umezawa, who also discovered kanamycin and bleomycin, as a drug which could prevent growth of a fungus causing rice blast disease. It was later found to inhibit bacterial growth also. It exists as a white, crystalline substance with the chemical formula C14H28ClN3O10 (kasugamycin hydrochloride). It is also known as kasumin. ==Mechanism of action== Like many of the known natural antibiotics, kasugamycin inhibits proliferation of bacteria by tampering with their ability to make new proteins, the ribosome being the major target. Kasugamycin inhibits protein synthesis at the step of translation initiation. Kasugamycin inhibition is thought to occur by direct competition with initiator transfer RNA. Recent experiments suggest that kasugamycin indirectly induces dissociation of P-site-bound fMet-tRNAfMet from 30S subunits through perturbation of the mRNA, thereby interfering with translation initiation. Kasugamycin specifically inhibits translation initiation of canonical but not of leaderless mRNA. For initiation on leaderless mRNA, the overlap between mRNA and kasugamycin is reduced and the binding of tRNA is further stabilized by the presence of the 50S subunit, minimizing Ksg efficacy. Kasugamycin also induces the formation of unusual 61S ribosomes in vivo, which are proficient in selectively translating leaderless mRNA. 61S particles are stable and are devoid of more than six proteins of the small subunit, including the functionally important proteins S1 and S12. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「kasugamycin」の詳細全文を読む スポンサード リンク
|