1kny
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(New page: 200px<br /><applet load="1kny" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kny, resolution 2.5Å" /> '''KANAMYCIN NUCLEOTIDYL...)
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Revision as of 17:20, 20 November 2007
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KANAMYCIN NUCLEOTIDYLTRANSFERASE
Overview
Kanamycin nucleotidyltransferase (KNTase) is a plasmid-coded enzyme, responsible for some types of bacterial resistance to aminoglycosides. The, enzyme deactivates various antibiotics by transferring a nucleoside, monophosphate group from ATP to the 4'-hydroxyl group of the drug., Detailed knowledge of the interactions between the protein and the, substrates may lead to the design of aminoglycosides less susceptible to, bacterial deactivation. Here we describe the structure of KNTase complexed, with both the nonhydrolyzable nucleotide analog AMPCPP and kanamycin., Crystals employed in the investigation were grown from poly(ethylene, glycol) solutions and belonged to the space group P2(1)2(1)2(1) with unit, cell dimensions of a = 57.3 A, b = 102.2 A, c = 101.8 A, and one dimer in, the asymmetric unit. Least-squares refinement of the model at 2.5 A, resolution reduced the crystallographic R factor to 16.8%. The binding, pockets for both the nucleotide and the antibiotic are extensively exposed, to the solvent and are composed of amino acid residues contributed by both, subunits in the dimer. There are few specific interactions between the, protein and the adenine ring of the nucleotide; rather the AMPCPP molecule, is locked into position by extensive hydrogen bonding between the alpha-, beta-, and gamma-phosphates and protein side chains. This, in part, may, explain the observation that the enzyme can utilize other nucleotides such, as GTP and UTP. The 4'-hydroxyl group of the antibiotic is approximately 5, A from the alpha-phosphorus of the nucleotide and is in the proper, orientation for a single in-line displacement attack at the, phosphorus.(ABSTRACT TRUNCATED AT 250 WORDS)
About this Structure
1KNY is a Single protein structure of sequence from Staphylococcus aureus with MG, APC and KAN as ligands. Full crystallographic information is available from OCA.
Reference
Structural investigation of the antibiotic and ATP-binding sites in kanamycin nucleotidyltransferase., Pedersen LC, Benning MM, Holden HM, Biochemistry. 1995 Oct 17;34(41):13305-11. PMID:7577914
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