Stereospecificity of aminoglycoside-ribosomal interactions.
Stereospecificity of aminoglycoside-ribosomal interactions.
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氨基糖苷-核糖体相互作用的立体特异性。
DOI：
10.1021/bi026086l
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发表时间：
2002
期刊：
影响因子：
2.9
通讯作者：
Rando,RobertR
中科院分区：
文献类型：
--
作者：
Ryu,DoHyun;Litovchick,Alexander;Rando,RobertR
氨基糖苷类抗生素与细菌rRNA的A位点解码区结合，导致错误翻译和/或过早的信息终止。此处确定氨基糖苷类与A位点RNA解码区构建体的结合仅具有弱立体特异性。以天然系列和对映体系列制备镜像原核A位点解码区构建体，并测试其与一系列氨基糖苷类的结合。一般来说，氨基糖苷类与d-系列解码区结构的结合亲和力比它们与对映体l-系列的结合亲和力高2 - 3倍。此外，L-新霉胺，天然存在的新霉胺的对映异构体的制备，并显示出约2倍更弱的结合比新霉胺的天然系列解码区构建体，结果与弱立体特异性结合一致。结合天然存在的新霉胺和其合成的对映异构体进一步评价与原核和真核核糖体的结合。这里，再次观察到弱立体特异性，其中l-新霉胺是约2倍的更有效的结合剂。然而，在功能水平上，非天然新霉胺证明抑制体外翻译与显着较低的效力（约5倍）thand-neamine。此外，l-和d-新霉胺对革兰氏阴性菌都有杀菌作用。coliandP.铜绿假单胞菌的MIC是新霉胺的8倍和3倍。有趣的是，l-新霉胺也抑制氨基糖苷类耐药菌E的生长。大肠杆菌，其表达能够磷酸化和解毒D-系列氨基糖苷类的激酶。这些观察结果表明，镜像氨基糖苷类可以避免某些形式的酶介导的耐药性。
Aminoglycoside antibiotics bind to the A-site decoding region of bacterial rRNA causing mistranslation and/or premature message termination. Aminoglycoside binding to A-site RNA decoding region constructs is established here to be only weakly stereospecific. Mirror-image prokaryotic A-site decoding region constructs were prepared in the naturald-series and the enantiomericl-series and tested for binding to a series of aminoglycosides. In general, aminoglycosides bind to thed-series decoding region constructs with 2−3-fold higher affinities than they bind to the enantiomericl-series. Moreover,l-neamine, the enantiomer of naturally occurringd-neamine, was prepared and shown to bind approximately 2-fold more weakly thand-neamine to the natural series decoding region construct, a result consistent with weakly stereospecific binding. The binding of naturally occurringd-neamine and its syntheticl-enantiomer was further evaluated with respect to binding to prokaryotic and eukaryotic ribosomes. Here, weak stereospecifcity was again observed withl-neamine being the more potent binder by a factor of approximately 2. However, on a functional level, unnaturall-neamine proved to inhibit in vitro translation with significantly lower potency (approximately 5-fold) thand-neamine. In addition, bothl- andd-neamine are bacteriocidal toward Gram-(−) bacteria.l-Neamine inhibits the growth ofE. coliandP. aeruginosawith 8- and 3-fold higher MIC thand-neamine. Interestingly,l-neamine also inhibits the growth of aminoglycoside-resistantE. coli,which expresses a kinase able to phosphorylate and detoxify aminoglycosides of thed-series. These observations suggest that mirror-image aminoglycosides may avoid certain forms of enzyme-mediated resistance.