IntroductionAPH(3')-IIIa is an aminoglycoside phosphotransferase enzyme that contributes to bacterial antibiotic resistance. This enzyme helps bacteria survive aminoglycoside antibiotics by phosphorylating the aminoglycoside, which reduces the drug's ability to bind to the bacterial ribosome. Because aminoglycosides are important antibiotics, understanding the structure and function of APH(3')-IIIa is useful for studying how resistance enzymes recognize and modify different drugs.[1] FunctionThe main function of APH(3')-IIIa is to inactivate aminoglycoside antibiotics. It does this by transferring a phosphate group from ATP to the antibiotic. Once the antibiotic is phosphorylated, it can no longer bind effectively to the bacterial ribosome, allowing the bacteria to resist the effects of the drug. StructureAPH(3')-IIIa contains structural features that are similar to other kinase-like enzymes. These features allow the enzyme to bind ATP and position the aminoglycoside substrate near the active site. The overall fold of the enzyme helps create a binding pocket where the antibiotic can interact with key residues. Active SiteThe active site of APH(3')-IIIa is important because this is where phosphate transfer occurs. Several residues near the active site help bind the substrate and orient it correctly for phosphorylation. In the interactive structure, selected residues are shown. Biological ImportanceAPH(3')-IIIa is biologically important because it is part of the larger problem of antibiotic resistance. By modifying aminoglycoside antibiotics, the enzyme lowers the effectiveness of these drugs. Studying this protein can help researchers better understand resistance mechanisms and potentially design inhibitors that restore antibiotic activity.
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Ross Tsevis
This page was last modified 21:08, 3 May 2026.
