Antibiotics that bind to the A site of the large ribosomal subunit can induce mRNA translocation
Antibiotics that bind to the A site of the large ribosomal subunit can induce mRNA translocation
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DOI：
10.1261/rna.035964.112
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发表时间：
2013-02-01
期刊：
影响因子：
4.5
通讯作者：
Noller, Harry F.
中科院分区：
文献类型：
--
作者：
Ermolenko, Dmitri N.;Cornish, Peter V.;Noller, Harry F.
在不存在延伸因子EF-G的情况下，核糖体在易位前（经典）和中间（杂交）易位状态之间经历自发的热驱动波动。这些波动不会导致生产性mRNA易位。扩展以前的研究结果，抗生素sparsomycin诱导易位，我们确定额外的肽基转移酶抑制剂，触发生产mRNA易位。我们发现，结合肽基转移酶A位点的抗生素诱导mRNA易位，而那些不占据A位点的抗生素不能诱导易位。使用单分子FRET，我们表明，易位诱导抗生素不加速亚基间的旋转，但仅通过转换的内在，热驱动的动力学的核糖体易位。我们的研究结果支持了这样的想法，核糖体是一个布朗棘轮机，其内在动力学可以纠正成单向移位的配体结合。
In the absence of elongation factor EF-G, ribosomes undergo spontaneous, thermally driven fluctuation between the pre-translocation (classical) and intermediate (hybrid) states of translocation. These fluctuations do not result in productive mRNA translocation. Extending previous findings that the antibiotic sparsomycin induces translocation, we identify additional peptidyl transferase inhibitors that trigger productive mRNA translocation. We find that antibiotics that bind the peptidyl transferase A site induce mRNA translocation, whereas those that do not occupy the A site fail to induce translocation. Using single-molecule FRET, we show that translocation-inducing antibiotics do not accelerate intersubunit rotation, but act solely by converting the intrinsic, thermally driven dynamics of the ribosome into translocation. Our results support the idea that the ribosome is a Brownian ratchet machine, whose intrinsic dynamics can be rectified into unidirectional translocation by ligand binding.