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Inhibition of glycine cleavage system by pyridoxine 5′‐phosphate causes synthetic lethality in glyA yggS and serA yggS in Escherichia coli
Author(s) -
Ito Tomokazu,
Hori Ran,
Hemmi Hisashi,
Downs Diana M.,
Yoshimura Tohru
Publication year - 2020
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14415
Subject(s) - biology , mutant , escherichia coli , serine hydroxymethyltransferase , biochemistry , synthetic lethality , glycine , serine , amino acid , phenotype , lethality , gene , enzyme , genetics
Summary The YggS/Ybl036c/PLPBP family includes conserved pyridoxal 5′‐phosphate (PLP)‐binding proteins that play a critical role in the homeostasis of vitamin B 6 and amino acids. Disruption of members of this family causes pleiotropic effects in many organisms by unknown mechanisms. In Escherichia coli , conditional lethality of the yggS and glyA (encoding serine hydroxymethyltransferase) has been described, but the mechanism of lethality was not determined. Strains lacking yggS and serA (3‐phosphoglycerate dehydrogenase) were conditionally lethality in the M9‐glucose medium supplemented with Gly. Analyses of vitamin B 6 pools found the high‐levels of pyridoxine 5′‐phosphate (PNP) in the two yggS mutants. Growth defects of the double mutants could be eliminated by overexpressing PNP/PMP oxidase (PdxH) to decrease the PNP levels. Further, a serA pdxH strain, which accumulates PNP in the presence of yggS , exhibited similar phenotype to serA yggS mutant. Together these data suggested the inhibition of the glycine cleavage (GCV) system caused the synthetic lethality. Biochemical assays confirmed that PNP disrupts the GCV system by competing with PLP in GcvP protein. Our data are consistent with a model in which PNP‐dependent inhibition of the GCV system causes the conditional lethality observed in the glyA yggS or serA yggS mutants.