Structural basis of the radical pair state in photolyases and cryptochromes

We present the structure of a photoactivated animal (6-4) photolyase in its radical pair state, captured by serial crystallography. We observe how a conserved asparigine moves towards the semiquinone FAD chromophore and stabilizes it by hydrogen bonding. Several amino acids around the final tryptophan radical rearrange, opening it up to the solvent. The structure explains how the protein environment stabilizes the radical pair state, which is crucial for function of (6-4) photolyases and cryptochromes.

Automated summary

This study presents the structure of a photoactivated (6-4) photolyase in its radical pair state, captured using serial crystallography. It explains how a conserved asparagine stabilizes the semiquinone FAD chromophore through hydrogen bonding, and how rearrangement of amino acids around the final tryptophan radical opens it up to the solvent. These findings highlight the importance of the protein environment in stabilizing the radical pair state for the function of (6-4) photolyases and cryptochromes.