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 EIIGlc , 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 EIIGlc 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 EIIGlc , 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 EIIGlc , which has implications for future strain engineering strategies.
Keywords: ptsG; EF-P; GntR2; glucose uptake; phosphotransferase system; translational control.
© 2020 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.