Fig. 5.
Model for SAHA-BPyne labeling of HDACs and HDAC-associated proteins. Incubation of proteomes with SAHA-BPyne results in selective binding to HDACs, which exist as parts of large multiprotein complexes. The BP group of SAHA-BPyne rests on the outer rim of HDAC active sites, resulting in UV light-induced photocross-linking to both HDACs and proximally associated proteins (green). More distally associated proteins (yellow) do not react with the probe. Proteome denaturation and click chemistry with a biotin-azide tag enables identification of SAHA-BPyne-labeled proteins by ABPP-MudPIT methods (sequential avidin enrichment, on-bead trypsin digestion, and shotgun LC-MS/MS analysis).