Salmonella enterica requires ApbC function for growth on tricarballylate: evidence of functional redundancy between ApbC and IscU.
Mutants of Salmonella enterica lacking apbC have nutritional and biochemical properties indicative of defects in [Fe-S] cluster metabolism. Here we show that apbC is required for S. enterica to use tricarballylate as a carbon and energy source. Tricarballylate catabolism requires three gene products, TcuA, TcuB, and TcuC. Of relevance to this work is the TcuB protein, which has two [4Fe-4S] clusters required for function, making it a logical target for the apbC effect. TcuB activity was 100-fold lower in an apbC mutant than in the isogenic apbC(+) strain. Genetic data show that derepression of the iscRSUA-hscAB-fdx-orf3 operon or overexpression of iscU from a plasmid compensates for the lack of ApbC during growth on tricarballylate. The studies described herein provide evidence that the scaffold protein IscU has a functional overlap with ApbC and that ApbC function is involved in the synthesis of active TcuB.
Boyd
Jeffrey M
JM
Department of Bacteriology, 1550 Linden Drive, University of Wisconsin, Madison, WI 53706, USA.
Lewis
Jeffrey A
JA
Escalante-Semerena
Jorge C
JC
Downs
Diana M
DM
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005816:Genetic Complementation Test; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D009154:Mutation; D010641:Phenotype; D016133:Polymerase Chain Reaction; D019779:Salmonella enterica / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014233:Tricarboxylic Acids / Q000737:chemistry / Q000378:metabolism*
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D014233:Tricarboxylic Acids