Identification of the Binding Site of Chroman-4-one-Based Sirtuin 2‑Selective Inhibitors using Photoaffinity Labeling in Combination with Tandem Mass Spectrometry

Photoaffinity labeling (PAL) was
used to identify the binding site
of chroman-4-one-based SIRT2-selective inhibitors. The photoactive
diazirine 4, a potent SIRT2 inhibitor, was subjected
to detailed photochemical characterization. In PAL experiments with
SIRT2, a tryptic peptide originating from the covalent attachment
of photoactivated 4 was identified. The peptide covers
both the active site of SIRT2 and the proposed binding site of chroman-4-one-based
inhibitors. A high-power LED was used as source for the monochromatic
UV light enabling rapid photoactivation.