3n4u

<StructureSection load='3n4u' size='340' side='right' caption='[[3n4u]], [[Resolution|resolution]] 2.20&Aring;' scene=''>

<table><tr><td colspan='2'>[[3n4u]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"streptococcus_casseliflavus"_vaughan_et_al._1979 "streptococcus casseliflavus" vaughan et al. 1979]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3N4U OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3N4U FirstGlance]. <br>

</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3n4t|3n4t]], [[3n4v|3n4v]]</td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">aph(2'')-Id ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=37734 "Streptococcus casseliflavus" Vaughan et al. 1979])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3n4u FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3n4u OCA], [http://pdbe.org/3n4u PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3n4u RCSB], [http://www.ebi.ac.uk/pdbsum/3n4u PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3n4u ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

Acquired resistance to aminoglycoside antibiotics primarily results from deactivation by three families of aminoglycoside-modifying enzymes. Here we report the kinetic mechanism and structure of the aminoglycoside phosphotransferase 2"-IVa (APH(2")-IVa), an enzyme responsible for resistance to aminoglycoside antibiotics in clinical enterococcal and staphylococcal isolates. The enzyme operates via a Bi Bi sequential mechanism in which the two substrates (ATP or GTP and an aminoglycoside) bind in a random manner. The APH(2")-IVa enzyme phosphorylates various 4,6-disubstituted aminoglycoside antibiotics with catalytic efficiencies (k(cat)/K(m)) of 1.5 x 10(3) to 1.2 x 10(6) (M(-1) s(-1)). The enzyme uses both ATP and GTP as the phosphate source, an extremely rare occurrence in the phosphotransferase and protein kinase enzymes. Based upon an analysis of the APH(2")-IVa structure, two overlapping binding templates specifically tuned for hydrogen bonding to either ATP or GTP have been identified and described. A detailed understanding of the structure and mechanism of the GTP-utilizing phosphotransferases is crucial for the development of either novel aminoglycosides or, more importantly, GTP-based enzyme inhibitors which would not be expected to interfere with crucial ATP-dependent enzymes.

Crystal structure and kinetic mechanism of aminoglycoside phosphotransferase-2''-IVa.,Toth M, Frase H, Antunes NT, Smith CA, Vakulenko SB Protein Sci. 2010 Jun 15. PMID:20556826<ref>PMID:20556826</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 3n4u" style="background-color:#fffaf0;"></div>

*[[Phosphotransferase|Phosphotransferase]]

[[Category: Streptococcus casseliflavus vaughan et al. 1979]]

[[Category: Frase, H]]

[[Category: Smith, C A]]

[[Category: Toth, M]]

[[Category: Vakulenko, S B]]

[[Category: Aminoglycoside]]

[[Category: Unknown function]]