Institute of Inorganic Chemistry, RWTH Aachen University, 52074, Aachen, Germany.
Institute of Biotechnology, RWTH Aachen University, 52074, Aachen, Germany.
Chemistry. 2024 Jan 22;30(5):e202303066. doi: 10.1002/chem.202303066. Epub 2023 Nov 30.
Artificial metalloenzymes have emerged as biohybrid catalysts that allow to combine the reactivity of a metal catalyst with the flexibility of protein scaffolds. This work reports the artificial metalloenzymes based on the β-barrel protein nitrobindin NB4, in which a cofactor [Co X(Me TACD-Mal)] X (X=Cl, Br; Me TACD=N,N ,N''-trimethyl-1,4,7,10-tetraazacyclododecane, Mal=CH CH CH NC H O ) was covalently anchored via a Michael addition reaction. These biohybrid catalysts showed higher efficiency than the free cobalt complexes for the oxidation of benzylic C(sp )-H bonds in aqueous media. Using commercially available oxone (2KHSO ⋅ KHSO ⋅ K SO ) as oxidant, a total turnover number of up to 220 and 97 % ketone selectivity were achieved for tetralin. As catalytically active intermediate, a mononuclear terminal cobalt(IV)-oxo species [Co(IV)=O] was generated by reacting the cobalt(II) cofactor with oxone in aqueous solution and characterized by ESI-TOF MS.
人工金属酶作为生物杂化催化剂已经出现，它可以将金属催化剂的反应性与蛋白质支架的灵活性结合起来。本工作报道了基于β-桶状蛋白硝吡咯啉 NB4 的人工金属酶，其中通过迈克尔加成反应将辅因子 [Co X(Me TACD-Mal)] X (X=Cl, Br; Me TACD=N,N,N''-trimethyl-1,4,7,10-tetraazacyclododecane, Mal=CH CH CH NC H O ) 共价连接到酶上。这些生物杂化催化剂在水相介质中氧化苄基 C(sp )-H 键的效率高于游离钴配合物。使用商业可得的过氧单硫酸盐（2KHSO ⋅ KHSO ⋅ K SO ）作为氧化剂，四氢萘的总周转数达到 220，酮的选择性达到 97%。作为催化活性中间体，通过在水溶液中用过氧单硫酸盐与钴(II)辅因子反应，生成单核末端钴(IV)-氧物种[Co(IV)=O]，并用 ESI-TOF MS 进行了表征。
