Translating ribosomes require elongation factor P (EF‐P) to incorporate consecutive prolines (XPPX) into nascent peptide chains. The proteome of Corynebacterium glutamicum ATCC 13032 contains a total of 1,468 XPPX motifs, many of which are found in proteins involved in primary and secondary metabolism. We show here that synthesis of EII^Glc, the glucose‐specific permease of the phosphoenolpyruvate (PEP): sugar phosphotransferase system (PTS) encoded by ptsG, is strongly dependent on EF‐P, as an efp deletion mutant grows poorly on glucose as sole carbon source. The amount of EII^Glc is strongly reduced in this mutant, which consequently results in a lower rate of glucose uptake. Strikingly, the XPPX motif is essential for the activity of EII^Glc, and substitution of the prolines leads to inactivation of the protein. Finally, translation of GntR2, a transcriptional activator of ptsG, is also dependent on EF‐P. However, its reduced amount in the efp mutant can be compensated for by other regulators. These results reveal for the first time a translational bottleneck involving production of the major glucose transporter EII^Glc, which has implications for future strain engineering strategies.

中文翻译：

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由于必需的聚脯氨酸基序，在谷氨酸棒杆菌中进行 EIIGlc 翻译需要延伸因子 P

翻译核糖体需要延伸因子 P (EF-P) 将连续脯氨酸 (XPPX) 结合到新生肽链中。谷氨酸棒状杆菌ATCC 13032的蛋白质组共包含 1,468 个 XPPX 基序，其中许多存在于参与初级和次级代谢的蛋白质中。我们在这里展示了 EII ^{Glc 的}合成，磷酸烯醇丙酮酸（PEP）的葡萄糖特异性渗透酶：由ptsG编码的糖磷酸转移酶系统（PTS），强烈依赖于 EF-P，因为efp缺失突变体在葡萄糖作为唯一碳源。EII ^Glc的用量在该突变体中显着降低，从而导致葡萄糖摄取率降低。引人注目的是，XPPX 基序对于 EII ^Glc的活性是必不可少的，脯氨酸的取代导致蛋白质失活。最后，ptsG 的转录激活因子GntR2 的翻译也依赖于 EF-P。然而，它在efp突变体中的减少量可以由其他监管机构补偿。这些结果首次揭示了涉及主要葡萄糖转运蛋白 EII ^Glc产生的翻译瓶颈，这对未来的菌株工程策略有影响。