Close-up of the cofactor binding site for the antibiotic resistance enzyme AAC(6')-Ii
This enzyme uses Acetyl-Co-enzyme A to chemically modify aminoglycoside antibiotics, thereby rendering the drugs useless. Intriguingly, the enzyme is related to a large family of acyl-transferases (GNAT superfamily). However the conformation of the co-factor when bond to these enzymes varies. Shown are the ways in which the co-factor from AAC(6’)-Ii (red) and those of two other related acyl-transferases (blue and green) are attached to the binding site seen in all GNAT enzymes.
Ribbon diagram of the aminoglycoside antibiotic modifying enzyme AAC(6')-Ii
This view highlights the different secondary structure elements, and shows the co-factor Acetyl Coenzyme A.
