The Crystal Structure of an [Fe]‐Hydrogenase–Substrate Complex Reveals the Framework for H2 Activation

An open and closed case: The structure of a binary complex of C176A [Fe]-hydrogenase with methylenetetrahydromethanopterin was solved at 2.15 Å resolution in an open conformation. A closed form of the complex was modeled on the basis of the experimentally determined structure. In this model, the iron-site trans to the acyl carbon is located next to the C14a and therefore considered as H2 binding site.