Front Cover: Isolable Cysteine Sulfenyl Iodide: Stabilization by a Molecular Cradle, Crystal Structure, and Biologically Relevant Reactivity (ChemBioChem 24/2025)

The cover illustrates the first isolable cysteine sulfenyl iodide (Cys-SI), stabilized by a nanosized molecular cradle installed at the N-terminus of cysteine. This stabilization enabled direct structural and reactivity studies of the long-hypothesized intermediate in cysteine thiol oxidation. The Cys-SI exhibits high electrophilicity toward nucleophiles, including an indole ring, providing chemical evidence supporting mechanistic proposals for iodine mediated protein modification. More details can be found in the Research Article by Kei Goto and co-workers (DOI: 10.1002/cbic.202500619).