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Cofactors and pathogens: Flavin mononucleotide and flavin adenine dinucleotide ( FAD) biosynthesis by the FAD synthase from Brucella ovis
Author(s) -
Moreno Andrea,
Taleb Victor,
Sebastián María,
AnozCarbonell Ernesto,
MartínezJúlvez Marta,
Medina Milagros
Publication year - 2022
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1002/iub.2576
Subject(s) - flavin mononucleotide , flavin adenine dinucleotide , flavoprotein , biochemistry , cofactor , flavin group , biosynthesis , biology , nucleotide , enzyme , phosphofructokinase 2 , atp synthase , stereochemistry , chemistry , gene
The biosynthesis of the flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), cofactors used by 2% of proteins, occurs through the sequential action of two ubiquitous activities: a riboflavinkinase (RFK) that phosphorylates the riboflavin (RF) precursor to FMN, and a FMN:adenylyltransferase (FMNAT) that transforms FMN into FAD. In most mammals two different monofunctional enzymes have each of these activities, but in prokaryotes a single bifunctional enzyme, FAD synthase (FADS), holds them. Differential structural and functional traits for RFK and FMNAT catalysis between bacteria and mammals, as well as within the few bacterial FADSs so far characterized, has envisaged the potentiality of FADSs from pathogens as targets for the development of species‐specific inhibitors. Here, we particularly characterize the FADS from the ovine pathogen Brucella ovis (BoFADS), causative agent of brucellosis. We show that BoFADS has RFK activity independently of the media redox status, but its FMNAT activity (in both forward and reverse senses) only occurs under strong reducing conditions. Moreover, kinetics for flavin and adenine nucleotides binding to the RFK site show that BoFADS binds preferentially the substrates of the RFK reaction over the products and that the adenine nucleotide must bind prior to flavin entrapment. These results, together with multiple sequence alignments and phylogenetic analysis, point to variability in the less conserved regions as contributing to the species‐specific features in prokaryotic FADSs, including those from pathogens, that allow them to adopt alternative strategies in FMN and FAD biosynthesis and overall flavin homeostasis.