Conserved Pyridoxal 5'-Phosphate Binding Protein YggS Impacts Amino Acid Metabolism through Pyridoxine 5'-Phosphate in Escherichia coli.

In this study, we determined that the pyridoxine (PN) sensitivity observed in the yggS-deficient E. coli was caused by the pyridoxine 5'-phosphate (PNP)-dependent overproduction of Val, which is toxic to E. coli The data suggest that the yggS mutation impacts Val accumulation by perturbing the biosynthetic of Thr from homoserine (Hse). Exogenous Hse inhibited the growth of the yggS mutant, caused further accumulation of PNP, and increased some intermediates in the Thr-Ile-Val metabolic pathways. Blocking the Thr biosynthetic pathway or decreasing of the intracellular PNP levels, abolished the perturbations of amino acid metabolism caused by the exogenous PN and Hse. Our data showed that a high concentration of intracellular PNP is the root cause of at least some of the pleiotropic phenotypes described for a yggS mutant of E. coli IMPORTANCE Recent studies showed that the deletion or mutation of YggS protein family causes pleiotropic effects in many organisms. Little is known about the cause, mechanism, and consequence of these diverse phenotypes. It was previously shown that yggS mutations in E. coli accumulate PNP and some metabolites in the Ile/Val biosynthetic pathway. This work reports that some exogenous stresses increase the aberrant accumulation of PNP in the yggS mutant. In addition, the current study provide evidences that some, but not all, of the phenotypes of the yggS mutant in E. coli are due to the elevated PNP. These results will contribute to continuing effort...

Source: Applied and Environmental Microbiology - March 21, 2019 Category: Microbiology Authors: Ito T, Yamamoto K, Hori R, Yamauchi A, Downs DM, Hemmi H, Yoshimura T Tags: Appl Environ Microbiol Source Type: research