| Autor: |
Berglund S; Physical Chemistry, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120, Uppsala, Sweden. Starla.glover@kemi.uu.se., Bassy C; Physical Chemistry, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120, Uppsala, Sweden. Starla.glover@kemi.uu.se., Kaya I; Department of Pharmaceutical Biosciences, Spatial Mass Spectrometry, Science for Life Laboratory, Uppsala University, Box 591, SE-75124 Uppsala, Sweden., Andrén PE; Department of Pharmaceutical Biosciences, Spatial Mass Spectrometry, Science for Life Laboratory, Uppsala University, Box 591, SE-75124 Uppsala, Sweden., Shtender V; Division of Applied Materials Science, Department of Materials Science and Engineering, Uppsala University, 75103 Uppsala, Sweden., Lasagna M; Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA., Tommos C; Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA., Magnuson A; Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120, Uppsala, Sweden., Glover SD; Physical Chemistry, Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, SE-75120, Uppsala, Sweden. Starla.glover@kemi.uu.se. |
| Abstrakt: |
Molecular catalysts based on abundant elements that function in neutral water represent an essential component of sustainable hydrogen production. Artificial hydrogenases based on protein-inorganic hybrids have emerged as an intriguing class of catalysts for this purpose. We have prepared a novel artificial hydrogenase based on cobaloxime bound to a de novo three alpha-helical protein, α 3 C, via a pyridyl-based unnatural amino acid. The functionalized de novo protein was characterised by UV-visible, CD, and EPR spectroscopy, as well as MALDI spectrometry, which confirmed the presence and ligation of cobaloxime to the protein. The new de novo enzyme produced hydrogen under electrochemical, photochemical and reductive chemical conditions in neutral water solution. A change in hydrogen evolution capability of the de novo enzyme compared with native cobaloxime was observed, with turnover numbers around 80% of that of cobaloxime, and hydrogen evolution rates of 40% of that of cobaloxime. We discuss these findings in the context of existing literature, how our study contributes important information about the functionality of cobaloximes as hydrogen evolving catalysts in protein environments, and the feasibility of using de novo proteins for development into artificial metalloenzymes. Small de novo proteins as enzyme scaffolds have the potential to function as upscalable bioinspired catalysts thanks to their efficient atom economy, and the findings presented here show that these types of novel enzymes are a possible product. |
