DIFFERENTIAL RATE OF RIBOSOMAL-PROTEIN SYNTHESIS IN ESCHERICHIA-COLI B-R
DIFFERENTIAL RATE OF RIBOSOMAL-PROTEIN SYNTHESIS IN ESCHERICHIA-COLI B-R
复制标题
DOI：
10.1016/0022-2836(74)90449-5
复制
发表时间：
1974-01-01
影响因子：
5.6
通讯作者：
BREMER, H
中科院分区：
文献类型：
--
作者：
DENNIS, PP;BREMER, H
测定大肠杆菌B/r在0.67 ~ 2.3倍/小时的不同稳态速率下的核糖体蛋白合成差异率αr（核糖体蛋白合成率/总蛋白合成率）。当生长速率大于1.2倍/小时时，αr与生长速率μ（倍/小时）成正比，即αr= 0.09 μ，由αr计算的核糖体效率（每个核糖体每秒聚合的氨基酸）为14 ~ 18个氨基酸/秒。当生长速率低于1.2倍/h时，αr逐渐大于0.09 μ，αr逐渐降低，atμ= 0.67,αr= 0.085，核糖体效率降低30%，相当于每个核糖体每秒产生10 ~ 13个氨基酸。这些结果表明，蛋白质与DNA的比值恒定为μ> 1.2，等于4 × 108 ~ 5 × 108个氨基酸/基因组。当μ< 1.2时，该比值逐渐减小，当μ= 0.67时，蛋白质与DNA的比值为3 × 108 ~ 4 × 108个氨基酸/基因组。这些关系通过直接测量不同稳定生长速率下的DNA、RNA和蛋白质的数量得到证实。此外，在从琥珀酸盐到葡萄糖最低培养基的营养转移后，测量了蛋白质积累。结果表明，在上移后的最初几分钟内，核糖体效率提高了约40%。
The differential rate of ribosomal protein synthesis,αr(ribosomal protein synthesis rate/total protein synthesis rate), was measured forEscherichia colistrain B/r growing at different steady-state rates ranging from 0.67 to 2.3 doublings/hour. For growth rates above 1.2 doublings/hour,αrwas found to be proportional to the growth rate μ (doublings/h), such thatαr= 0.09 μ, and the ribosome efficiency (amino acids polymerized/second per ribosome), calculated fromαr, was found to be 14 to 18 amino acids/second per ribosome. With decreasing growth rates below 1.2 doublings/hour,αrwas found to be increasingly greater than 0.09 μ and the ribosome efficiency gradually decreased such that atμ= 0.67,αr= 0.085, and the ribosome efficiency was reduced by 30% and was equal to 10 to 13 ammo acids/second per ribosome. These results imply that the protein to DNA ratio is constant forμ> 1.2 and equal to 4 × 108to 5 × 108amino acids/genome. Forμ< 1.2, this ratio gradually decreases such that atμ= 0.67, protein to DNA = 3 × 108to 4 × 108amino acids/genome. These relationships were verified by direct measurements of the amounts of DNA, RNA and protein at different steady-state growth rates. In addition, protein accumulation was measured following a nutritional shift-up from succinate to glucose minimal medium. The results indicate that the ribosome efficiency increases by approximately 40% within the first few minutes following the shift-up.