Chemical Proteomics with Sulfonyl Fluoride Probes Reveals Selective Labeling of Functional Tyrosines in Glutathione Transferases

SummaryChemical probes have great potential for identifying functional residues in proteins in crude proteomes. Here we studied labeling sites of chemical probes based on sulfonyl fluorides (SFs) on plant and animal proteomes. Besides serine proteases and many other proteins, SF-based probes label Tyr residues in glutathione transferases (GSTs). The labeled GSTs represent four different GST classes that share less than 30% sequence identity. The targeted Tyr residues are located at similar positions in the promiscuous substrate binding site and are essential for GST function. The high selectivity of SF-based probes for functional Tyr residues in GSTs illustrates how these probes can be used for functional studies of GSTs and other proteins in crude proteomes.

Graphical AbstractFigure optionsDownload full-size imageDownload high-quality image (288 K)Download as PowerPoint slideHighlights► Sulfonyl fluoride probes label diverse GSTs in both plant and mouse proteomes ► GSTs are labeled on Tyr residues in unconserved substrate binding pockets ► Labeled Tyr residues are essential for GST function