Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0620, USA.
J Mol Biol. 2010 Mar 12;396(5):1310-8. doi: 10.1016/j.jmb.2009.12.042. Epub 2010 Jan 4.
The mechanisms for de novo protein folding differ significantly between bacteria and eukaryotes, as evidenced by the often observed poor yields of native eukaryotic proteins upon recombinant production in bacterial systems. Polypeptide synthesis rates are faster in bacteria than in eukaryotes, but the effects of general variations in translation rates on protein folding efficiency have remained largely unexplored. By employing Escherichia coli cells with mutant ribosomes whose translation speed can be modulated, we show here that reducing polypeptide elongation rates leads to enhanced folding of diverse proteins of eukaryotic origin. These results suggest that in eukaryotes, protein folding necessitates slow translation rates. In contrast, folding in bacteria appears to be uncoupled from protein synthesis, explaining our findings that a generalized reduction in translation speed does not adversely impact the folding of the endogenous bacterial proteome. Utilization of this strategy has allowed the production of a native eukaryotic multidomain protein that has been previously unattainable in bacterial systems and may constitute a general alternative to the production of aggregation-prone recombinant proteins.
新生蛋白质折叠的机制在细菌和真核生物之间有显著差异，这一点可以从在细菌系统中重组生产时，真核生物蛋白质往往产量低这一现象得到证实。细菌中的多肽合成速度比真核生物快，但翻译速度的普遍变化对蛋白质折叠效率的影响在很大程度上仍未得到探索。通过使用突变核糖体的大肠杆菌细胞，其翻译速度可以调节，我们在这里表明，降低多肽延伸速度会导致多种源自真核生物的蛋白质折叠增强。这些结果表明，在真核生物中，蛋白质折叠需要较慢的翻译速度。相比之下，细菌中的折叠似乎与蛋白质合成脱钩，这解释了我们的发现，即普遍降低翻译速度不会对内源性细菌蛋白质组的折叠产生不利影响。这种策略的利用使得生产以前在细菌系统中无法获得的天然真核生物多结构域蛋白质成为可能，并且可能构成一种生产易于聚集的重组蛋白质的通用替代方法。
