Axel Magalon

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The formation of active membrane-bound nitrate reductase A in Escherichia coli requires the presence of three subunits, NarG, NarH and NarI, as well as a fourth protein, NarJ, that is not part of the active nitrate reductase. In narJ strains, both NarG and NarH subunits are associated in an unstable and inactive NarGH complex. A significant activation of(More)
Understanding when and how metal cofactor insertion occurs into a multisubunit metalloenzyme is of fundamental importance. Molybdenum cofactor insertion is a tightly controlled process that involves specific interactions between the proteins that promote cofactor delivery, enzyme-specific chaperones, and the apoenzyme. In the assembly pathway of the(More)
l-Cysteine desulfurases provide sulfur to several metabolic pathways in the form of persulfides on specific cysteine residues of an acceptor protein for the eventual incorporation of sulfur into an end product. IscS is one of the three Escherichia coli l-cysteine desulfurases. It interacts with FdhD, a protein essential for the activity of formate(More)
The hybG gene product from Escherichia coli has been identified as a chaperone-like protein acting in the maturation of hydrogenases 1 and 2. It was shown that HybG forms a complex with the precursor of the large subunit of hydrogenase 2. As with HypC, which is the chaperone-like protein involved in hydrogenase 3 maturation, the N-terminal cysteine residue(More)
A novel class of molecular chaperones co-ordinates the assembly and targeting of complex metalloproteins by binding to an amino-terminal peptide of the cognate substrate. We have previously shown that the NarJ chaperone interacts with the N-terminus of the NarG subunit coming from the nitrate reductase complex, NarGHI. In the present study, NMR structural(More)
Under anaerobic conditions and in the presence of nitrate, the facultative anaerobe Escherichia coli synthesises an electron-transport chain comprising a primary dehydrogenase and the terminal membrane-bound nitrate reductase A (NarGHI). This review focuses on recent advances obtained on the structure and function of the three protein subunits of(More)
A four-gene operon (nrcDEFN) was identified within a conjugative element that allows Thermus thermophilus to use nitrate as an electron acceptor. Three of them encode homologues to components of bacterial respiratory chains: NrcD to ferredoxins; NrcF to iron-sulfur-containing subunits of succinate-quinone oxidoreductase (SQR); and NrcN to type-II NADH(More)
The biogenesis of respiratory complexes is a multistep process that requires finely tuned coordination of subunit assembly, metal cofactor insertion, and membrane-anchoring events. The dissimilatory nitrate reductase of the bacterial anaerobic respiratory chain is a membrane-bound heterotrimeric complex nitrate reductase A (NarGHI) carrying no less than(More)
An evolutionary tree of key enzymes from the Complex-Iron-Sulfur-Molybdoenzyme (CISM) superfamily distinguishes "ancient" members, i.e. enzymes present already in the last universal common ancestor (LUCA) of prokaryotes, from more recently evolved subfamilies. The majority of the presented subfamilies and, as a consequence, the Molybdo-enzyme superfamily as(More)
The interaction of the hydrogenase maturation endopeptidase HycI with its substrate, the precursor of the large subunit, was studied. Replacement of conserved amino-acid residues in HycI, which have been shown to bind a cadmium ion from the crystallization buffer in crystals of HybD (endopeptidase for hydrogenase 2), abolished or strongly reduced processing(More)