Iron‐sulfur cluster carrier proteins involved in the assembly of Escherichia coli NADH:ubiquinone oxidoreductase (complex I). Issue 1 (23rd October 2018)

• Record Type: Journal Article
• Authors: Burschel, Sabrina; Kreuzer Decovic, Doris; Nuber, Franziska; Stiller, Marie; Hofmann, Maud; Zupok, Arkadiusz; Siemiatkowska, Beata; Gorka, Michal; Leimkühler, Silke; Friedrich, Thorsten
• Is Part Of: Molecular microbiology. Volume 111:Issue 1(2019)
• Page Start: 31
• Page End: 45
• Publication Date: 2018-10-23
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.14137
• Languages: English
• ISSNs: 0950-382X

Abstract

Summary: The NADH:ubiquinone oxidoreductase (respiratory complex I) is the main entry point for electrons into the Escherichia coli aerobic respiratory chain. With its sophisticated setup of 13 different subunits and 10 cofactors, it is anticipated that various chaperones are needed for its proper maturation. However, very little is known about the assembly of E. coli complex I, especially concerning the incorporation of the iron‐sulfur clusters. To identify iron‐sulfur cluster carrier proteins possibly involved in the process, we generated knockout strains of NfuA, BolA, YajL, Mrp, GrxD and IbaG that have been reported either to be involved in the maturation of mitochondrial complex I or to exert influence on the clusters of bacterial complex. We determined the NADH and succinate oxidase activities of membranes from the mutant strains to monitor the specificity of the individual mutations for complex I. The deletion of NfuA, BolA and Mrp led to a decreased stability and partially disturbed assembly of the complex as determined by sucrose gradient centrifugation and native PAGE. EPR spectroscopy of cytoplasmic membranes revealed that the BolA deletion results in the loss of the binuclear Fe/S cluster N1b. Abstract : The incorporation of Fe/S clusters into Escherichia coli respiratory complex I is essential for the proper assembly of the complex. However, it has not been known yet which Fe/S cluster carrier proteins are involved in this process. Hence, we have characterized a series of strains lacking putative Fe/S cluster carrier proteins with respect to complex I activity and assembly and we show that BolA, Mrp and NfuA are involved in the incorporation of Fe/S clusters in complex I.