Pagnier Adrien, Martin Lydie, Zeppieri Laura, Nicolet Yvain, Fontecilla-Camps Juan C
Metalloproteins Unit, Institut de Biologie Structurale Commissariat à l'Energie Atomique et aux Energies Renouvelables-Centre National de la Recherche Scientifique-Université Grenoble Alpes, 38044 Grenoble Cedex 9, France.
Metalloproteins Unit, Institut de Biologie Structurale Commissariat à l'Energie Atomique et aux Energies Renouvelables-Centre National de la Recherche Scientifique-Université Grenoble Alpes, 38044 Grenoble Cedex 9, France
Proc Natl Acad Sci U S A. 2016 Jan 5;113(1):104-9. doi: 10.1073/pnas.1515842113. Epub 2015 Dec 22.
The synthesis and assembly of the active site [FeFe] unit of [FeFe]-hydrogenases require at least three maturases. The radical S-adenosyl-l-methionine HydG, the best characterized of these proteins, is responsible for the synthesis of the hydrogenase CO and CN(-) ligands from tyrosine-derived dehydroglycine (DHG). We speculated that CN(-) and the CO precursor (-):CO2H may be generated through an elimination reaction. We tested this hypothesis with both wild type and HydG variants defective in second iron-sulfur cluster coordination by measuring the in vitro production of CO, CN(-), and (-):CO2H-derived formate. We indeed observed formate production under these conditions. We conclude that HydG is a multifunctional enzyme that produces DHG, CN(-), and CO at three well-differentiated catalytic sites. We also speculate that homocysteine, cysteine, or a related ligand could be involved in Fe(CO)x(CN)y transfer to the HydF carrier/scaffold.
[FeFe]-氢化酶活性位点[FeFe]单元的合成与组装至少需要三种成熟酶。自由基S-腺苷-L-甲硫氨酸HydG是这些蛋白质中研究得最透彻的，它负责从酪氨酸衍生的脱氢甘氨酸（DHG）合成氢化酶的CO和CN(-)配体。我们推测CN(-)和CO前体(-):CO2H可能通过消除反应生成。我们通过测量CO、CN(-)和(-):CO2H衍生的甲酸的体外产生，对野生型和在第二个铁硫簇配位方面有缺陷的HydG变体进行了这一假设的测试。我们确实在这些条件下观察到了甲酸的产生。我们得出结论，HydG是一种多功能酶，在三个明显不同的催化位点产生DHG、CN(-)和CO。我们还推测，同型半胱氨酸、半胱氨酸或相关配体可能参与Fe(CO)x(CN)y转移至HydF载体/支架。
