Solution Studies of Isepamicin and Conformational Comparisons between Isepamicin and Butirosin A When Bound to an Aminoglycoside 6‘-N-Acetyltransferase Determined by NMR Spectroscopy

NMR spectroscopy, combined with molecular modeling, was used to determine the conformations of isepamicin and butirosin A in the active site of aminoglycoside 6'-N-acetyltransferase-Ii [AAC-(6')-Ii]. The results suggest two enzyme-bound conformers for isepamicin and one for butirosin A. The dihedral angles that describe the glycosidic linkage between the A and B rings for the two conformers of AAC(6')-Ii-bound isepamicin were phi AB = -7.9 +/- …