Directed Evolution of Aminoglycoside Phosphotransferase (3′) Type IIIa Variants That Inactivate Amikacin but Impose Significant Fitness Costs
Figure 1
Model of artificially evolved aminoglycoside phosphotransferase (3′)-IIIa, based upon crystal structure (1L8T) of the wild-type enzyme [23] rendered in PyMOL.
The putative beneficial mutations are colored orange, the catalytic D190 residue is green), adenosine diphosphate is yellow and magnesium is pink. Kanamycin is blue, while the “extra” moiety that differentiates amikacin from kanamycin is red.