Structural Analysis of Aminoglycoside Modifying Enzymes: Towards Rational Drug Design

Abstract

Bacterial resistance to the aminoglycoside antibiotics is a major health concern because of the elimination of a therapeutic option for the treatment of nosocomial infections. Clinical resistance is commonly caused by the acquisition of genes that encode an aminoglycoside modifying enzyme. These enzymes offer a potential therapeutic target in the fight against aminoglycoside resistance. By gaining a structural understanding of these enzymes the potential is created for rational drug design. The research presented here deals with structural studies on two aminoglycoside resistance enzymes. First the initial stages of structural determination for the bifunctional Aminoglycoside 6'-N-Acetyl transferase Aminoglycoside 2''-O-Phosphotransferase (AAC(6')-APH(2")) including the optimization of the purification procedure for this enzyme. The second enzyme is the Aminoglycoside 3'-O-Phosphotransferase (APH(3')IIIa). Computational studies on this enzyme have been carried out in order to determine models for aminoglycoside binding and also to search for potential enzyme inhibitors. The molecular docking studies for both the aminoglycoside binding and inhibitor search involved the development of a number of novel methods to improve the chance of obtaining a correct model, and to aid in the analysis of the data from the docking studies. These methods have the potential to be applied in future structure based drug design