Genest Olivier, Neumann Meina, Seduk Farida, Stöcklein Walter, Méjean Vincent, Leimkühler Silke, Iobbi-Nivol Chantal
Laboratoire de Chimie Bactérienne, Institut de Biologie Structurale et Microbiologie-CNRS, 31 chemin Joseph Aiguier, Marseille cedex 20, France.
J Biol Chem. 2008 Aug 1;283(31):21433-40. doi: 10.1074/jbc.M802954200. Epub 2008 Jun 2.
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.
含钼酶的生物合成是一个复杂的过程，涉及将复杂的钼辅因子插入到有活性的脱辅基蛋白中。对于许多钼酶而言，三甲胺氧化物还原酶TorA的成熟需要一种特定的伴侣蛋白。这种伴侣蛋白（TorD）与信号肽和脱辅基TorA的核心区域相互作用。通过随机诱变，我们确定TorD的α-螺旋5在核心区域结合中起关键作用，且这种结合驱动TorA的成熟。此外，我们首次表明TorD与钼辅因子生物合成成分相互作用，包括辅因子合成的最后一种酶MobA以及辅因子的前体形式钼蝶呤。最后，我们证明TorD也结合辅因子的成熟形式钼蝶呤 - 鸟嘌呤二核苷酸。因此，我们提出TorD作为一个平台，在钼辅因子插入TorA催化位点之前连接其合成的最后一步。
