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Yi Yang Juliatiek Roestamadji Shahriar Mobashery Ron Orlando 《Bioorganic & medicinal chemistry letters》1998,8(24):2393-3494
Four novel aminoglycoside-based affinity inactivators were shown to covalently modify the active site of aminoglycoside 3′-phosphotransferase type IIa (APH(3′)-IIa), an important resistance factor in bacteria for aminoglycoside antibiotics. Standard peptide mapping techniques failed with this enzyme. A novel mass spectroscopic analysis which combines protease digestion on the instrument probe, followed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is described which permitted rapid identification of the sites of protein modification. By this new technique, Glu-3 and Asp-23 were identified as active-site residues, the side chains of which potentially may serve as counter ions for the ammonium functionalities at positions 6′, and 1 and 3 of the antibiotic substrates, respectively. These findings contradict previous assertions that the C-terminal third of the enzyme should form the active site, by placing the active site clearly in the N-terminal portion of the enzyme. 相似文献
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Juliatiek Roestamadji Shahriar Mobashery 《Bioorganic & medicinal chemistry letters》1998,8(24):1898-3488
Aminoglycoside 3′-phosphotransferase type IIa [APH(3′)-IIa] is a member of the family of bacterial aminoglycoside-modifying enzymes. Bacteria that harbor these enzymes are resistant to aminoglycoside antibiotics. Four aminoglycoside-based affinity inactivators were synthesized and were shown to be both substrates and inactivators for APH(3′)-IIa. These affinity inactivators are N-bromoacetylated derivatives of neamine, an aminoglycoside antibiotic, where the bromoacetyl moiety in each was introduced regiospecifically at a different amine of the parent compound. 相似文献
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