PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-1 (1)
 

Clipboard (0)
None
Journals
Authors
Year of Publication
Document Types
1.  IscA/SufA Paralogs Are Required for the [4Fe-4S] Cluster Assembly in Enzymes of Multiple Physiological Pathways in Escherichia coli under Aerobic Growth Conditions 
The Biochemical journal  2009;420(3):463-472.
Synopsis
IscA/SufA paralogs are the members of the iron-sulfur cluster assembly machinery in Escherichia coli. While deletion of either IscA or SufA has only a mild effect on cell growth, deletion of both IscA and SufA results in a null-growth phenotype in minimal medium under aerobic growth conditions. Here we report that cell growth of the iscA/sufA double mutant (E. coli strain in which both iscA and sufA had been in-frame-deleted) can be partially restored by supplementing with BCAAs (branched-chain amino acids) and thiamin. We further demonstrate that deletion of IscA/SufA paralogs blocks the [4Fe-4S] cluster assembly in IlvD (dihydroxyacid dehydratase) of the BCAA biosynthesis pathway in E. coli cells under aerobic conditions and that addition of the iron-bound IscA/SufA efficiently promotes the [4Fe-4S] cluster assembly in IlvD and restores the enzyme activity in vitro, suggesting that IscA/SufA may act as an iron donor for the [4Fe-4S] cluster assembly under aerobic conditions. Additional studies reveal that IscA/SufA are also required for the [4Fe-4S] cluster assembly in protein ThiC of the thiamin biosynthesis pathway, aconitase B of the citrate acid cycle, and endonuclease III of the DNA base excision repair pathway in E. coli under aerobic conditions. Nevertheless, deletion of IscA/SufA does not significantly affect the [2Fe-2S] cluster assembly in the redox transcription factor SoxR, ferredoxin, and the siderophore-iron reductase FhuF. The results suggest that the biogenesis of the [4Fe-4S] clusters and the [2Fe-2S] clusters may have distinct pathways and that IscA/SufA paralogs are essential for the [4Fe-4S] cluster assembly, but are dispensable for the [2Fe-2S] cluster assembly in E. coli under aerobic conditions.
doi:10.1042/BJ20090206
PMCID: PMC2776711  PMID: 19309314
aconitase; branched-chain amino acids; dihydroxyacid dehydratase; iron-sulfur clusters; IscA/SufA paralogs; thiamin

Results 1-1 (1)