Enzymes
UniProtKB help_outline | 260 proteins |
Enzyme class help_outline |
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Reaction participants Show >> << Hide
- Name help_outline a gentamycin Identifier CHEBI:90218 Charge 2 Formula C17H28N2O6R6 SMILEShelp_outline C1[C@H]([C@@H]([C@H]([C@H](O1)O[C@H]2[C@@H](C[C@@H]([C@H]([C@@H]2O)O[C@H]3O[C@@H]([C@H]([C@@H]([C@H]3*)*)*)C*)[NH3+])[NH3+])O)*)* 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline GTP Identifier CHEBI:37565 (Beilstein: 5211792) help_outline Charge -4 Formula C10H12N5O14P3 InChIKeyhelp_outline XKMLYUALXHKNFT-UUOKFMHZSA-J SMILEShelp_outline Nc1nc2n(cnc2c(=O)[nH]1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 85 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline a gentamycin 2''-phosphate Identifier CHEBI:90219 Charge 0 Formula C17H27N2O9PR6 SMILEShelp_outline C1[C@H]([C@@H]([C@H]([C@H](O1)O[C@H]2[C@@H](C[C@@H]([C@H]([C@@H]2O)O[C@H]3O[C@@H]([C@H]([C@@H]([C@H]3*)*)*)C*)[NH3+])[NH3+])OP([O-])(=O)[O-])*)* 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline GDP Identifier CHEBI:58189 Charge -3 Formula C10H12N5O11P2 InChIKeyhelp_outline QGWNDRXFNXRZMB-UUOKFMHZSA-K SMILEShelp_outline Nc1nc2n(cnc2c(=O)[nH]1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 169 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,176 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:48872 | RHEA:48873 | RHEA:48874 | RHEA:48875 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Revisiting the nucleotide and aminoglycoside substrate specificity of the bifunctional aminoglycoside acetyltransferase(6')-Ie/aminoglycoside phosphotransferase(2'')-Ia enzyme.
Frase H., Toth M., Vakulenko S.B.
The bifunctional aminoglycoside-modifying enzyme aminoglycoside acetyltransferase(6')-Ie/aminoglycoside phosphotransferase(2″)-Ia, or AAC(6')-Ie/APH(2″)-Ia, is the major source of aminoglycoside resistance in gram-positive bacterial pathogens. In previous studies, using ATP as the cosubstrate, it ... >> More
The bifunctional aminoglycoside-modifying enzyme aminoglycoside acetyltransferase(6')-Ie/aminoglycoside phosphotransferase(2″)-Ia, or AAC(6')-Ie/APH(2″)-Ia, is the major source of aminoglycoside resistance in gram-positive bacterial pathogens. In previous studies, using ATP as the cosubstrate, it was reported that the APH(2″)-Ia domain of this enzyme is unique among aminoglycoside phosphotransferases, having the ability to inactivate an unusually broad spectrum of aminoglycosides, including 4,6- and 4,5-disubstituted and atypical. We recently demonstrated that GTP, and not ATP, is the preferred cosubstrate of this enzyme. We now show, using competition assays between ATP and GTP, that GTP is the exclusive phosphate donor at intracellular nucleotide levels. In light of these findings, we reevaluated the substrate profile of the phosphotransferase domain of this clinically important enzyme. Steady-state kinetic characterization using the phosphate donor GTP demonstrates that AAC(6')-Ie/APH(2″)-Ia phosphorylates 4,6-disubstituted aminoglycosides with high efficiency (k(cat)/K(m) = 10(5)-10(7) M(-1) s(-1)). Despite this proficiency, no resistance is conferred to some of these antibiotics by the enzyme in vivo. We now show that phosphorylation of 4,5-disubstituted and atypical aminoglycosides are negligible and thus these antibiotics are not substrates. Instead, these aminoglycosides tend to stimulate an intrinsic GTPase activity of the enzyme. Taken together, our data show that the bifunctional enzyme efficiently phosphorylates only 4,6-disubstituted antibiotics; however, phosphorylation does not necessarily result in bacterial resistance. Hence, the APH(2″)-Ia domain of the bifunctional AAC(6')-Ie/APH(2″)-Ia enzyme is a bona fide GTP-dependent kinase with a narrow substrate profile, including only 4,6-disubstituted aminoglycosides. << Less
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Nucleotide sequence analysis of the gene specifying the bifunctional 6'-aminoglycoside acetyltransferase 2'-aminoglycoside phosphotransferase enzyme in Streptococcus faecalis and identification and cloning of gene regions specifying the two activities.
Ferretti J.J., Gilmore K.S., Courvalin P.
The gene specifying the bifunctional 6'-aminoglycoside acetyltransferase [AAC(6')] 2"-aminoglycoside phosphotransferase [APH(2")] enzyme from the Streptococcus faecalis plasmid pIP800 was cloned in Escherichia coli. A single protein with an apparent molecular weight of 56,000 was specified by this ... >> More
The gene specifying the bifunctional 6'-aminoglycoside acetyltransferase [AAC(6')] 2"-aminoglycoside phosphotransferase [APH(2")] enzyme from the Streptococcus faecalis plasmid pIP800 was cloned in Escherichia coli. A single protein with an apparent molecular weight of 56,000 was specified by this cloned determinant as detected in minicell experiments. Nucleotide sequence analysis revealed the presence of an open reading frame capable of specifying a protein of 479 amino acids and with a molecular weight of 56,850. The deduced amino acid sequence of the bifunctional AAC(6')-APH(2") gene product possessed two regions of homology with other sequenced resistance proteins. The N-terminal region contained a sequence that was homologous to the chloramphenicol acetyltransferase of Bacillus pumilus, and the C-terminal region contained a sequence homologous to the aminoglycoside phosphotransferase of Streptomyces fradiae. Subcloning experiments were performed with the AAC(6')-APH(2") resistance determinant, and it was possible to obtain gene segments independently specifying the acetyltransferase and phosphotransferase activities. These data suggest that the gene specifying the AAC(6')-APH(2") resistance enzyme arose as a result of a gene fusion. << Less