The kinetics of ribosomal peptidyl transfer revisited
The kinetics of ribosomal peptidyl transfer revisited
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DOI：
10.1016/j.molcel.2008.04.010
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发表时间：
2008-06-06
期刊：
影响因子：
16
通讯作者：
Ehrenberg, Mans
中科院分区：
文献类型：
--
作者：
Johansson, Magnus;Bouakaz, Elli;Ehrenberg, Mans
蛋白质合成的速度决定了细菌的生长速度。目前对蛋白质伸长率的生化估计很小，与活细胞中的蛋白质伸长率不相容。利用一个针对速度和准确性进行优化的无细胞蛋白质合成系统，我们估计了不同温度下从P位的肽-tRNA到A位的同源氨基酰-tRNA的肽转移速率。我们发现这些速率比以前测量的要大得多，并且与在富含介质中生长的大肠杆菌细胞的蛋白质伸长速度完全兼容。我们发现了多肽转移的大的活化热和小的活化熵，类似于氨基酰tRNA的A位类似物的这些参数的实验估计。我们的工作为蛋白质合成的生化研究打开了一个有用的动力学窗口，弥合了核糖体功能的体外和体内数据之间的差距。
The speed of protein synthesis determines the growth rate of bacteria. Current biochemical estimates of the rate of protein elongation are small and incompatible with the rate of protein elongation in the living cell. With a cell-free system for protein synthesis, optimized for speed and accuracy, we have estimated the rate of peptidyl transfer from a peptidyl-tRNA in P site to a cognate aminoacyl-tRNA in A site at various temperatures. We have found these rates to be much larger than previously measured and fully compatible with the speed of protein elongation for E. coli cells growing in rich medium. We have found large activation enthalpy and small activation entropy for peptidyl transfer, similar to experimental estimates of these parameters for A site analogs of aminoacyl-tRNA. Our work has opened a useful kinetic window for biochemical studies of protein synthesis, bridging the gap between in vitro and in vivo data on ribosome function.