Resistance mutations generate divergent antibiotic susceptibility profiles against translation inhibitors
Resistance mutations generate divergent antibiotic susceptibility profiles against translation inhibitors
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DOI：
10.1073/pnas.1605127113
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发表时间：
2016-07-19
影响因子：
11.1
通讯作者：
Ferguson, Andrew D.
中科院分区：
文献类型：
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作者：
Cocozaki, Alexis I.;Altman, Roger B.;Ferguson, Andrew D.
赋予翻译抑制剂抗性的突变通常改变rRNA的结构。因此，当一个共同的核糖体结合位点受到干扰时，可能会出现对不同结构抗生素类别的敏感性降低，这会显著降低这些药物的临床效用。翻译抑制剂阴霉素和四环素干扰tRNA与30S核糖体小亚基上的氨酰-tRNA位点的结合。然而，两种阴霉素耐药突变显示出意想不到的差异抗生素敏感性。16 S大肠杆菌rRNA中的突变体U1060 A对两种抗生素均具有耐药性，而突变体U1052 G同时对负霉素具有耐药性，对四环素具有超敏感性。结合微生物、生物化学、单分子荧光转移实验和X射线晶体学，我们确定了U1052G突变体70S E中的特定结构缺陷。大肠杆菌核糖体，解释其不同的负霉素和四环素敏感性谱。出乎意料的是，U1052G突变体核糖体具有与其过敏性相关的第二个四环素结合位点。先前未鉴定的抗生素结合位点的产生提高了将来在耐药病原体中鉴定类似现象的前景。
Mutations conferring resistance to translation inhibitors often alter the structure of rRNA. Reduced susceptibility to distinct structural antibiotic classes may, therefore, emerge when a common ribosomal binding site is perturbed, which significantly reduces the clinical utility of these agents. The translation inhibitors negamycin and tetracycline interfere with tRNA binding to the aminoacyl-tRNA site on the small 30S ribosomal subunit. However, two negamycin resistance mutations display unexpected differential antibiotic susceptibility profiles. Mutant U1060A in 16S Escherichia coli rRNA is resistant to both antibiotics, whereas mutant U1052G is simultaneously resistant to negamycin and hypersusceptible to tetracycline. Using a combination of microbiological, biochemical, single-molecule fluorescence transfer experiments, and X-ray crystallography, we define the specific structural defects in the U1052G mutant 70S E. coli ribosome that explain its divergent negamycin and tetracycline susceptibility profiles. Unexpectedly, the U1052G mutant ribosome possesses a second tetracycline binding site that correlates with its hypersusceptibility. The creation of a previously unidentified antibiotic binding site raises the prospect of identifying similar phenomena in antibiotic-resistant pathogens in the future.