Front Cover: Structural Basis of the Light‐Switchable Interaction between an Azobenzene Side Chain in a Biosynthetic Protein and α ‐Cyclodextrin (ChemistryOpen 1/2026)

The Front Cover illustrates the specific host/guest complex formation between the light-switchable noncanonical amino acid /p/-(phenylazo)-L-phenylalanine (Pap) in its low-energy /trans/-state and α-cyclodextrin (α-CD), which is elucidated by X-ray crystallographic analysis of super-folder green fluorescent protein (sfGFP) as carrier for the Pap side chain. Upon illumination with mild UV-A light, Pap switches to the /cis/-configuration and the complex dissociates, which can be utilized for the affinity purification of sfGFP(39Pap) on an α-CD affinity column. More information can be found in the Research Article by Arne Skerra and co-workers (DOI: 10.1002/open.202500471).