Ribose 5-phosphate: the key metabolite bridging the metabolisms of nucleotides and amino acids during stringent response in Escherichia coli?

Abstract

The bacterial stringent response and its effector alarmone guanosine penta- or tetra – phosphates (p)ppGpp are vital for bacterial tolerance and survival of various stresses in environments (including antibiotics) and host cells (viru-lence). (p)ppGpp does so by binding to its numerous target proteins and repro-graming bacterial transcriptome to tune down the synthesis of nucleotides and rRNA/tRNA, and up-regulate amino acid biosynthesis genes. Recent identifica-tion of more novel (p)ppGpp direct binding proteins in Escherichia coli and their deep studies have unveiled unprecedented details of how (p)ppGpp coordi-nates the nucleotide and amino acid metabolic pathways upon stringent re-sponse; however, the mechanistic link between nucleotide and amino acid me-tabolisms remains still incompletely understood. Here we propose the metab-olite ribose 5’-phosphate as the key link between nucleotide and amino acid metabolisms and a working model integrating both the transcriptional and metabolic effects of (p)ppGpp on E. coli physiological adaptation during the stringent response.

Keywords

• (p)ppgpp
• stringent response
• nucleotide
• amino acid
• ribose 5’-phosphate