A connection between iron–sulfur cluster metabolism and the biosynthesis of 4-amino-5-hydroxymethyl-2-methylpyrimidine pyrophosphate in Salmonella enterica

Abstract

Several cellular pathways have been identified which affect the efficiency of thiamine biosynthesis inSalmonella enterica. Mutants defective in iron–sulfur (Fe–S) cluster metabolism are less efficient at synthesis of the pyrimidine moiety of thiamine. These mutants are compromised for the conversion of aminoimidazole ribotide (AIR) to 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate (HMP-P), not the synthesis of AIR. The gene product ThiC contains potential ligands for an Fe–S cluster that are required for functionin vivo. The conversion of AIR to HMP-P is sensitive to oxidative stress, and variants of ThiC have been identified that have increased sensitivity to oxidative growth conditions. The data are consistent with ThiC or an as-yet-unidentified protein involved in HMP-P synthesis containing an Fe–S cluster required for its physiological function.