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[NiFe] hydrogenases are complex model enzymes for the reversible cleavage of dihydrogen (H2). However, structural determinants of efficient H2 binding to their [NiFe] active site are not properly understood. Here, we present crystallographic and vibrational‐spectroscopic insights into the unexplored structure of the H2‐binding [NiFe] intermediate. Using an F420‐reducing [NiFe]‐hydrogenase from Methanosarcina barkeri as a model enzyme, we show that the protein backbone provides a strained chelating scaffold that tunes the [NiFe] active site for efficient H2 binding and conversion. The protein matrix also directs H2 diffusion to the [NiFe] site via two gas channels and allows the distribution of electrons between functional protomers through a subunit‐bridging FeS cluster. Our findings emphasize the relevance of an atypical Ni coordination, thereby providing a blueprint for the design of bio‐inspired H2‐conversion catalysts. [ABSTRACT FROM AUTHOR]

Keywords: [NiFe]-hydrogenase; biocatalysis; in situ spectroscopy; metalloenzymes; vibrational spectroscopy EN [NiFe]-hydrogenase biocatalysis in situ spectroscopy metalloenzymes vibrational spectroscopy 1 1 1 07/10/21 20210712 NES 210712 B Metalloenzymes b In their Research Article on page 15854, Christian Lorent, Marius Horch, Lars Lauterbach, Ingo Zebger et al. explore redox intermediates of [NiFe]-hydrogenases by an advanced experimental approach for solvated, lyophilized, and crystallized metalloenzymes. Frontispiece: Exploring Structure and Function of Redox Intermediates in [NiFe]-Hydrogenases by an Advanced Experimental Approach for Solvated, Lyophilized and Crystallized Metalloenzymes [NiFe]-hydrogenase, biocatalysis, in situ spectroscopy, metalloenzymes, vibrational spectroscopy. [Extracted from the article]