Fig. 4. Detection of H4S1/S1ph interacting proteins.

(a) Design of photoreactive peptide probes 1 (Dz-H4S1) and 2 (Dz-H4S1ph). The N-terminal acetyl groups were replaced with a diazirine-containing moiety. (b) Scheme for the crosslinking reaction (carbene insertion). (c) Crosslinking pull-down experiment using probes 1 and 2. Photoaffinity-captured proteins were enriched by biotin-streptavidin affinity purification and detected by streptavidin–HRP. H4S1-specific (arrows) and H4S1ph-specific bands (arrowheads) are indicated.