Producing organism
Streptomyces sp.
Biological activity
antibacterial activity
A newly isolated strain of Streptomyces sp. produces a new nucleoside antibiotic, ascamycin and the corresponding dealanyl derivative. The structure of ascamycin was determined to be 2-chloro-9-β-[5-O-(N-L-alanyl)sulfamoyl-D-ribofuranosyl]-adenine. Remarkable selective toxicity of ascamycin compared to the dealanyl derivative was accounted for on the basis of a dealanylating enzyme present in the envelope of sensitive bacteria. After dealanylation, it becomes permeable to cell membrane.
isolation and structural determination
  • Isono K, Uramoto M, Osada H, Ubukata M, Kusakabe H, Koyama T, Miyata N, Sethi SK, McCloskey JA.: Structure and biological activity of ascamycin, a new nucleoside antibiotic.
    Nucleic Acids Symp Ser, (15): 65-67 (1984) PMID: 6395097
  • Isono K, Uramoto M, Kusakabe H, Miyata N, Koyama T, Ubukata M, Sethi SK, McCloskey JA.: Ascamycin and dealanylascamycin, nucleoside antibiotics from Streptomyces sp.
    J Antibiot, 37(6): 670-672 (1984) PMID: 6547710
  • synthesis
  • Ubukata M, Osada H, Isono K.: Synthesis and biological activity of nucleoside antibiotics, ascamycin and its amino acid analogs.
    Nucleic Acids Symp Ser, (16): 81-83 (1985) PMID: 3841391
  • biological activities
  • Osada H, Isono K.: Mechanism of action and selective toxicity of ascamycin, a nucleoside antibiotic.
    Antimicrob Agents Chemother, 27(2): 230-233 (1985) PMID: 2580481
  • Osada H, Isono K.: Purification and characterization of ascamycin-hydrolysing aminopeptidase from Xanthomonas citri.
    Biochem J, 233(2): 459-463 (1986) PMID: 3754135
  • Osada H, Isono K.: Occurrence of an ascamycin dealanylating enzyme, Xc-aminopeptidase, in mammalian cell membranes and susceptibility to ascamycin.
    J Antibiot, 39(2): 286-293 (1986) PMID: 3514563
  • Sudo T, Shinohara K, Dohmae N, Takio K, Usami R, Horikoshi K, Osada H.: Isolation and characterization of the gene encoding an aminopeptidase involved in the selective toxicity of ascamycin toward Xanthomonas campestris pv. citri.
    Biochem J, 319(Pt 1): 99-102 (1996) PMID: 8870654
  • Additional information