TY  - JOUR
A1  - Zupok, Arkadiusz
A1  - Górka, Michał Jakub
A1  - Siemiatkowska, Beata
A1  - Skirycz, Aleksandra
A1  - Leimkühler, Silke
T1  - Iron-Dependent Regulation of Molybdenum Cofactor Biosynthesis Genes in Escherichia coli
JF  - Journal of bacteriology
N2  - Molybdenum cofactor (Moco) biosynthesis is a complex process that involves the coordinated function of several proteins. In recent years it has become obvious that the availability of iron plays an important role in the biosynthesis of Moco. First, the MoaA protein binds two (4Fe-4S] clusters per monomer. Second, the expression of the moaABCDE and moeAB operons is regulated by FNR, which senses the availability of oxygen via a functional NFe-4S) cluster. Finally, the conversion of cyclic pyranopterin monophosphate to molybdopterin requires the availability of the L-cysteine desulfurase IscS, which is a shared protein with a main role in the assembly of Fe-S clusters. In this report, we investigated the transcriptional regulation of the moaABCDE operon by focusing on its dependence on cellular iron availability. While the abundance of selected molybdoenzymes is largely decreased under iron-limiting conditions, our data show that the regulation of the moaABCDE operon at the level of transcription is only marginally influenced by the availability of iron. Nevertheless, intracellular levels of Moco were decreased under iron-limiting conditions, likely based on an inactive MoaA protein in addition to lower levels of the L-cysteine desulfurase IscS, which simultaneously reduces the sulfur availability for Moco production. IMPORTANCE FNR is a very important transcriptional factor that represents the master switch for the expression of target genes in response to anaerobiosis. Among the FNR-regulated operons in Escherichia coli is the moaABCDE operon, involved in Moco biosynthesis. Molybdoenzymes have essential roles in eukaryotic and prokaryotic organisms. In bacteria, molybdoenzymes are crucial for anaerobic respiration using alternative electron acceptors. This work investigates the connection of iron availability to the biosynthesis of Moco and the production of active molybdoenzymes.
KW  - Escherichia coli
KW  - FNR
KW  - iron regulation
KW  - iron-sulfur cluster
KW  - anaerobic respiration
KW  - molybdenum cofactor
Y1  - 2019
U6  - https://doi.org/10.1128/JB.00382-19
SN  - 0021-9193
SN  - 1098-5530
VL  - 201
IS  - 17
PB  - American Society for Microbiology
CY  - Washington
ER  - 
TY  - JOUR
A1  - Burschel, Sabrina
A1  - Decovic, Doris Kreuzer
A1  - Nuber, Franziska
A1  - Stiller, Marie
A1  - Hofmann, Maud
A1  - Zupok, Arkadiusz
A1  - Siemiatkowska, Beata
A1  - Gorka, Michal Jakub
A1  - Leimkühler, Silke
A1  - Friedrich, Thorsten
T1  - Iron-sulfur cluster carrier proteins involved in the assembly of Escherichia coli NADH
BT  - ubiquinone oxidoreductase (complex I)
JF  - Molecular microbiology
N2  - 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.
Y1  - 2018
U6  - https://doi.org/10.1111/mmi.14137
SN  - 0950-382X
SN  - 1365-2958
VL  - 111
IS  - 1
SP  - 31
EP  - 45
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - THES
A1  - Górka, Michal Jakub
T1  - Establishing a pipeline for identification of protein- protein interactions using different native fractionation methods
Y1  - 2017
ER  -