PMID: 23275343
Dagil R, O'Shea C, Nykjaer A, Bonvin AM, Kragelund BB
Gentamicin Binds to Megalin as a Competitive Inhibitor Using the Common Ligand Binding Motif of Complement Type Repeats.
J Biol Chem. 2012 Dec 27.
is an aminoglycoside widely used in treatments of, in particular, enterococcal, mycobacterial and severe gram-negative bacterial infections. Large doses of gentamicin cause nephrotoxicity and ototoxicity, entering the cell via the receptor megalin. Until now, no structural information has been available to describe the interaction with gentamicin in atomic detail, and neither have any three-dimensional structures of domains from the human megalin receptor been solved. To address this gap in our knowledge, we have solved the NMR structure of the tenth complement type repeat of human megalin and investigated its interaction with gentamicin. Using NMR titration data in HADDOCK we have generated a three-dimensional model describing the complex between megalin and gentamicin. Gentamicin binds to megalin with low affinity and exploits the common ligand binding motif previously described (Jensen et al. (2006) J Mol Biol 362, 700-716) utilizing the indole side chain of Trp1126 and the negatively charged residues Asp1129, Asp1131 and Asp1133. Binding to megalin is highly similar to gentamicin binding to calreticulin. We discuss the impact of this novel insight for the future structure-based design of gentamicin antagonists.