期刊
JOURNAL OF MOLECULAR BIOLOGY
卷 374, 期 4, 页码 1065-1076出版社
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jmb.2007.10.003
关键词
S12; decoding; paromomycin; domain closure; miscoding
The fidelity of aminoacyl-tRNA selection by the ribosome depends on a conformational switch in the decoding center of the small ribosomal subunit induced by cognate but not by near-cognate aminoacyl-tRNA. The aminoglycosides paromomycin and streptomycin bind to the decoding center and induce related structural rearrangements that explain their observed effects on miscoding. Structural and biochemical studies have identified ribosomal protein S12 (as well as specific nucleotides in 16S ribosomal RNA) as a critical molecular contributor in distinguishing between cognate and near-cognate tRNA species as well as in promoting more global rearrangements in the small subunit, referred to as closure. Here we use a mutational approach to define contributions made by two highly conserved loops in S12 to the process of tRNA selection. Most S12 variant ribosomes tested display increased levels of fidelity (a restrictive phenotype). Interestingly, several variants, K42A and R53A, were substantially resistant to the miscoding effects of paromomycin. Further characterization of the compromised paromomycin response identified a probable second, fidelity-modulating binding site for paromomycin in the 16S ribosomal RNA that facilitates closure of the small subunit and compensates for defects associated with the S12 mutations. (C) 2007 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据