The structure determination of an enzymatic inactivation product of 3',4'-dideoxykanamycin B.

Sir: As described in the preceding communi-cation1), 3' , 4/-dideoxykanamycin B (DKB) was inactivated in the presence of ATP by an enzyme preparation obtained from Es-cherichia coli JR66/W677 carrying R factor. In this communication, the structure of the inactivated antibiotic is shown to be 3', 4'-dideoxykanamycin B-2/r-adenylate by nuclear magnetic resonance study. We reported that the inactivated DKB was a mono-adenylyl DKB from the data of UV and IR, color reactions, and elementary analysis (C18H37N5O8-C10H12N5O6P-3H2O). The proton magnetic resonance (pmr) spectrum of inactivated DKBin D2O solution (20 mg/0.3 ml, pH 8.0, Fig. 1) using tetramethylsilane as an external reference (£=0) showed signals for two protons at d8.63 and d 8.85 ppm attributable to the adenine-ring protons, six protons at 8 6.53, 5.28, 4.98, 4.83 and ca. 4.6 ppm (2-H). These six protons were assigned to the ribose-ring protons by successive double resonance experiments and the comparison with disodium 5'-adenylate in D2Osolution (15mg/0.3ml, Table 1). Therefore, these observations confirm the presence of one mole of 5'-adenylic acid in the molecule. Irradiation at d 5.45 ppm (J=3.6, 1"-H) caused the complex signal at 8 4.3 ppm (2/r-H) to collapse to a triplet type signal. Irradiation at d 3.49 ppm (3"-H) caused the same region (2"-H) å to collapse to a broad doublet type signal. Irradiation at d 5.45 and 3.49ppm (triple resonance) caused the same position (2r/-H) to collapse to a doublet (J=8.0). Irradiation at £ 4.32 ppm (2"-H) caused the signals at d 5.45 ppm (1"-H) and 3 3.50 ppm (3"-H) to collapse to a singlet and doublet (J=10.0), respectively. The chemical shift of the 3;/-H to high-field was attributed to the amino group. These results indicate that the (1"-H), (2"-H) and (3"-H) signals described above are attributable to the 3-amino-glucose moiety (Table 2). In the case of