Hamasaki K, Rando R R
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Biochemistry. 1997 Oct 7;36(40):12323-8. doi: 10.1021/bi970962r.
RNA constructs prepared from wild-type and mutant (1555(G)) human mitochondrial 12S RNA were studied with respect to their abilities to specifically bind aminoglycoside antibiotics. The 1555(G) point mutation had previously been found to be associated with hereditary deafness induced by aminoglycosides. It is shown here that the 1555(G) RNA analog stoichiometrically binds aminoglycosides with high affinities, while the wild-type construct does not bind aminoglycosides at all. Analogous mutations in a 16S bacterial rRNA construct show the opposite behavior. Bacterial 16S rRNA constitutes the functional target for aminoglycoside antibiotics. While the wild-type 16S rRNA decoding region construct binds aminoglycosides stoichiometrically with binding affinities in the micromolar range, the mutant is unable to specifically bind aminoglycosides. These results demonstrate the importance of a specific GC base pair in aminoglycoside binding in both the human and the bacterial rRNA constructs. These studies also provide quantitative evidence in support of the hypothesis that the 1555(G) point mutation in human mitochondrial 12S RNA causes aminoglycoside induced deafness.
对由野生型和突变型（1555(G)）人线粒体12S RNA制备的RNA构建体进行了研究，考察它们特异性结合氨基糖苷类抗生素的能力。此前已发现1555(G)点突变与氨基糖苷类药物诱发的遗传性耳聋有关。本文表明，1555(G) RNA类似物能以化学计量比与氨基糖苷类药物高亲和力结合，而野生型构建体则完全不结合氨基糖苷类药物。16S细菌rRNA构建体中的类似突变表现出相反的行为。细菌16S rRNA是氨基糖苷类抗生素的功能靶点。野生型16S rRNA解码区构建体能以化学计量比与氨基糖苷类药物结合，结合亲和力在微摩尔范围内，而突变体则无法特异性结合氨基糖苷类药物。这些结果证明了特定GC碱基对在人及细菌rRNA构建体中氨基糖苷类药物结合中的重要性。这些研究还提供了定量证据，支持人线粒体12S RNA中的1555(G)点突变导致氨基糖苷类药物诱发耳聋这一假说。
