School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA.
Present Address: Molecular Engineering and Sciences, Institute for Protein Design, University of Washington, Seattle, WA, 98195-1655, USA.
Chemistry. 2020 May 15;26(28):6240-6246. doi: 10.1002/chem.202000204. Epub 2020 Apr 28.
Hybrid protein-organometallic catalysts are being explored for selective catalysis of a number of reactions, because they utilize the complementary strengths of proteins and of organometallic complex. Herein, we present an artificial hydrogenase, StrepH2, built by incorporating a biotinylated [Fe-Fe] hydrogenase organometallic mimic within streptavidin. This strategy takes advantage of the remarkable strength and specificity of biotin-streptavidin recognition, which drives quantitative incorporation of the biotinylated diironhexacarbonyl center into streptavidin, as confirmed by UV/Vis spectroscopy and X-ray crystallography. FTIR spectra of StrepH2 show characteristic peaks at shift values indicative of interactions between the catalyst and the protein scaffold. StrepH2 catalyzes proton reduction to hydrogen in aqueous media during photo- and electrocatalysis. Under photocatalytic conditions, the protein-embedded catalyst shows enhanced efficiency and prolonged activity compared to the isolated catalyst. Transient absorption spectroscopy data suggest a mechanism for the observed increase in activity underpinned by an observed longer lifetime for the catalytic species Fe Fe when incorporated within streptavidin compared to the biotinylated catalyst in solution.
杂化蛋白-金属有机催化剂正在被探索用于许多反应的选择性催化，因为它们利用了蛋白质和金属有机配合物的互补优势。在此，我们介绍了一种人工氢化酶 StrepH2，它是通过将生物素化的 [Fe-Fe] 氢化酶金属有机模拟物整合到链霉亲和素中来构建的。这种策略利用了生物素-链霉亲和素识别的显著强度和特异性，该识别驱动生物素化二铁六羰基中心定量整合到链霉亲和素中，这一点通过紫外/可见光谱和 X 射线晶体学得到了证实。StrepH2 的傅里叶变换红外光谱显示出在催化剂和蛋白质支架之间相互作用的特征峰，其位移值表明了这一点。StrepH2 在光催化和电催化条件下于水相介质中催化质子还原为氢气。在光催化条件下，与分离的催化剂相比，嵌入蛋白质的催化剂显示出更高的效率和更长的活性。瞬态吸收光谱数据表明，观察到的活性增加的机制是由在与溶液中的生物素化催化剂相比时，当整合到链霉亲和素中时，催化物种 Fe Fe 的寿命更长所支撑的。
