title: Evidence that COG0325 proteins are involved in PLP homeostasis.
abstract: Pyridoxal 5'-phosphate (PLP) is an essential cofactor for nearly 60Escherichia colienzymes but is a highly reactive molecule that is toxic in its free form. How PLP levels are regulated and how PLP is delivered to target enzymes are still open questions. The COG0325 protein family belongs to the fold-type III class of PLP enzymes and binds PLP but has no known biochemical activity although it occurs in all kingdoms of life. Various pleiotropic phenotypes of theE. coliCOG0325 (yggS) mutant have been reported, some of which were reproduced and extended in this study. Comparative genomic, genetic and metabolic analyses suggest that these phenotypes reflect an imbalance in PLP homeostasis. TheE. coli yggSmutant accumulates the PLP precursor pyridoxine 5'-phosphate (PNP) and is sensitive to an excess of pyridoxine but not of pyridoxal. The pyridoxine toxicity phenotype is complemented by the expression of eukaryoticyggSorthologs. It is also suppressed by the presence of amino acids, specifically isoleucine, threonine and leucine, suggesting the PLP-dependent enzyme transaminase B (IlvE) is affected. These genetic results lay a foundation for future biochemical studies of the role of COG0325 proteins in PLP homeostasis.
authors.affiliation: Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA.
authors.forename: Laurence
authors.initials: L
authors.lastname: Prunetti
authors.affiliation: Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA.
authors.forename: Basma
authors.initials: B
authors.lastname: El Yacoubi
authors.affiliation: Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA.
authors.forename: Cara R
authors.initials: CR
authors.lastname: Schiavon
authors.affiliation: Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA.
authors.forename: Ericka
authors.initials: E
authors.lastname: Kirkpatrick
authors.affiliation: Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL, USA.
authors.forename: Lili
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Bailly
authors.affiliation: Department of Molecular and Cellular Biology & Genome Center, University of California, Davis, CA, USA.
authors.forename: Mona
authors.initials: M
authors.lastname: El Badawi-Sidhu
authors.affiliation: Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Harrison
authors.affiliation: Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL, USA.
authors.forename: Jesse F
authors.initials: JF
authors.lastname: Gregory
authors.affiliation: Department of Molecular and Cellular Biology & Genome Center, University of California, Davis, CA, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Fiehn
authors.affiliation: Department of Horticultural Sciences, University of Florida, Gainesville, FL, USA.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Hanson
authors.affiliation: Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA.
authors.forename: Valérie
authors.initials: V
authors.lastname: de Crécy-Lagard