title: Crystal structures of two aminoglycoside kinases bound with a eukaryotic protein kinase inhibitor.
abstract: Antibiotic resistance is recognized as a growing healthcare problem. To address this issue, one strategy is to thwart the causal mechanism using an adjuvant in partner with the antibiotic. Aminoglycosides are a class of clinically important antibiotics used for the treatment of serious infections. Their usefulness has been compromised predominantly due to drug inactivation by aminoglycoside-modifying enzymes, such as aminoglycoside phosphotransferases or kinases. These kinases are structurally homologous to eukaryotic Ser/Thr and Tyr protein kinases and it has been shown that some can be inhibited by select protein kinase inhibitors. The aminoglycoside kinase, APH(3')-IIIa, can be inhibited by CKI-7, an ATP-competitive inhibitor for the casein kinase 1. We have determined that CKI-7 is also a moderate inhibitor for the atypical APH(9)-Ia. Here we present the crystal structures of CKI-7-bound APH(3')-IIIa and APH(9)-Ia, the first structures of a eukaryotic protein kinase inhibitor in complex with bacterial kinases. CKI-7 binds to the nucleotide-binding pocket of the enzymes and its binding alters the conformation of the nucleotide-binding loop, the segment homologous to the glycine-rich loop in eukaryotic protein kinases. Comparison of these structures with the CKI-7-bound casein kinase 1 reveals features in the binding pockets that are distinct in the bacterial kinases and could be exploited for the design of a bacterial kinase specific inhibitor. Our results provide evidence that an inhibitor for a subset of APHs can be developed in order to curtail resistance to aminoglycosides.
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors.forename: Desiree H
authors.initials: DH
authors.lastname: Fong
authors.forename: Bing
authors.initials: B
authors.lastname: Xiong
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Hwang
authors.forename: Albert M
authors.initials: AM
authors.lastname: Berghuis
mesh_terms: D000277:Adjuvants, Pharmaceutic / Q000494:pharmacology; D001665:Binding Sites; D047389:Casein Kinase I / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D015195:Drug Design; D005057:Eukaryotic Cells / Q000378:metabolism*; D007546:Isoquinolines / Q000737:chemistry*; D019868:Kanamycin Kinase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000277:Adjuvants, Pharmaceutic; D007546:Isoquinolines; D009711:Nucleotides; D047428:Protein Kinase Inhibitors; C058815:N-(2-aminoethyl)-5-chloroisoquinoline-8-sulfonamide; D017853:Phosphotransferases (Alcohol Group Acceptor); D019868:Kanamycin Kinase; D047389:Casein Kinase I