The complete 1H NMR assignments of aminoglycoside antibiotics and conformational studies of butirosin A through the use of 2D NMR spectroscopy

The complete proton assignments of the aminoglycoside antibiotics, butirosin A, kanamycin A and kanamycin B, at pH 6.5 have been made through the use of various homonuclear and heteronuclear 2D NMR methods. Butirosin A NOESY experiments suggest a stacking arrangement between the xylose and 2,6-diamino-2,6-dideoxyglucose rings, while the 2-deoxystreptamine ring and its substituent, the (S)-4-amino-2-hydroxybutyryl group, extend away from the stacked rings. Informative long-range NOEs were observed for butirosin A but not with kanamycin A or kanamycin B. Many intra-ring NOEs were observed with all three aminoglycosides that confirm the proton assignments made in this study.