Secondary structure changes as the potential H2 sensing mechanism of group D [FeFe]-hydrogenases.

[FeFe]-hydrogenases function as both H₂ catalysts and sensors. While catalysis is well investigated, details regarding the H₂ sensing mechanism are limited. Here, we relate protein structure changes to H₂ sensing, similar to light-driven bio-sensors. Our results highlight how identical cofactors incorporated in alternative protein scaffolds serve different functions in nature. [ABSTRACT FROM AUTHOR]