FIGURE 1.

Diversity in aminoglycoside antibiotics and the phosphotransferases that inactivate them. A, structures of representative aminoglycosides from different classes. B, cladogram for aminoglycoside phosphotransferases (APHs). Thirty-one amino acid sequences of APHs were aligned using ClustalX version 2.0 (60) and the radial style tree was produced using FigTree version 1.2.3. GenBank protein codes are noted in parentheses. APH(9)-Ia is highlighted in a box with thick black line and the other APHs whose crystal structures have been determined (APH(3′)-IIa/IIIa and APH(2″)-IIa are highlighted in boxes with thin black lines.