Tanifuji Kazuki, Lee Chi Chung, Ohki Yasuhiro, Tatsumi Kazuyuki, Hu Yilin, Ribbe Markus W
Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697-3900 (USA).
Department of Chemistry, Graduate School of Science and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan).
Angew Chem Int Ed Engl. 2015 Nov 16;54(47):14022-5. doi: 10.1002/anie.201507646. Epub 2015 Oct 16.
Nitrogenase catalyzes substrate reduction at its cofactor center ((Cit)MoFe7S9C; designated M-cluster). Here, we report the formation of an artificial, nitrogenase-mimicking enzyme upon insertion of a synthetic model complex (Fe6S9(SEt)2; designated Fe6(RHH)) into the catalytic component of nitrogenase (designated NifDK(apo)). Two Fe6(RHH) clusters were inserted into NifDK(apo), rendering the conformation of the resultant protein (designated NifDK(Fe)) similar to the one upon insertion of native M-clusters. NifDK(Fe) can work together with the reductase component of nitrogenase to reduce C2H2 in an ATP-dependent reaction. It can also act as an enzyme on its own in the presence of Eu(II)DTPA, displaying a strong activity in C2H2 reduction while demonstrating an ability to reduce CN(-) to C1-C3 hydrocarbons in an ATP-independent manner. The successful outcome of this work provides the proof of concept and underlying principles for continued search of novel enzymatic activities based on this approach.
固氮酶在其辅因子中心((Cit)MoFe7S9C;称为M簇)催化底物还原。在此,我们报道了将一种合成模型配合物(Fe6S9(SEt)2;称为Fe6(RHH))插入固氮酶的催化组分(称为NifDK(apo))后形成了一种人工模拟固氮酶的酶。两个Fe6(RHH)簇被插入到NifDK(apo)中,使得所得蛋白质(称为NifDK(Fe))的构象与插入天然M簇后的构象相似。NifDK(Fe)可以与固氮酶的还原酶组分协同作用,在依赖ATP的反应中还原C2H2。在Eu(II)DTPA存在的情况下,它自身也可以作为一种酶,在C2H2还原中表现出很强的活性,同时还展示出以不依赖ATP的方式将CN(-)还原为C1 - C3烃类的能力。这项工作的成功结果为基于这种方法继续寻找新型酶活性提供了概念验证和基本原理。