Anti-sulfonylbenzoate antibodies as a tool for the detection of nucleotide-binding proteins for functional proteomics.

Proteins that bind ATP and GTP are important cellular components. We developed an immunological approach to selectively tag nucleotide-binding proteins based on the use of 5'-[4-(fluorosulfonyl)benzoyl]adenosine and 5'-[4-(fluorosulfonyl)benzoyl]guanosine affinity tags and an antibody against 4-(sulfonyl)benzoate. Detection follows affinity labeling, gel electrophoresis, and ester bond cleavage to expose the epitope. Trial analyses of labeled proteins from lymphoid cells identified multiple ATP-binding proteins, including chaperones, actin, kinases, an RNA splicing factor, a membrane ATPase, and ATP synthase.