Dedicated metallochaperone connects apoenzyme and molybdenum cofactor biosynthesis components.
The biogenesis of molybdenum-containing enzymes is a sophisticated process involving the insertion of a complex molybdenum cofactor into competent apoproteins. As for many molybdoenzymes, the maturation of trimethylamine-oxide reductase TorA requires a private chaperone. This chaperone (TorD) interacts with the signal peptide and the core of apo-TorA. Using random mutagenesis, we established that alpha-helix 5 of TorD plays a key role in the core binding and that this binding drives the maturation of TorA. In addition, we showed for the first time that TorD interacts with molybdenum cofactor biosynthesis components, including MobA, the last enzyme of cofactor synthesis, and Mo-molybdopterin, the precursor form of the cofactor. Finally we demonstrated that TorD also binds the mature molybdopterin-guanine dinucleotide form of the cofactor. We thus propose that TorD acts as a platform connecting the last step of the synthesis of the molybdenum cofactor just before its insertion into the catalytic site of TorA.
Laboratoire de Chimie Bactérienne, Institut de Biologie Structurale et Microbiologie-CNRS, 31 chemin Joseph Aiguier, Marseille cedex 20, France.
Olivier
O
Genest
Meina
M
Neumann
Farida
F
Seduk
Walter
W
Stöcklein
Vincent
V
Méjean
Silke
S
Leimkühler
Chantal
C
Iobbi-Nivol
D001051:Apoenzymes / Q000737:chemistry*; D020134:Catalytic Domain; D003067:Coenzymes / Q000096:biosynthesis* / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D006147:Guanine / Q000737:chemistry; D008667:Metalloproteins / Q000096:biosynthesis* / Q000737:chemistry; D008954:Models, Biological; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D008968:Molecular Conformation; D000090006:Molybdenum Cofactors; D009154:Mutation; D010089:Oxidoreductases, N-Demethylating / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011621:Pteridines / Q000737:chemistry; D020798:Two-Hybrid System Techniques
D001051:Apoenzymes; D003067:Coenzymes; D003432:Cross-Linking Reagents; D029968:Escherichia coli Proteins; D006147:Guanine; D008667:Metalloproteins; D018832:Molecular Chaperones; D000090006:Molybdenum Cofactors; D010089:Oxidoreductases, N-Demethylating; D011621:Pteridines; C088083:TorD protein, E coli; C022261:molybdopterin; C023186:trimethylamine dehydrogenase