Integrating two Affinity Pull-down Strategies with Mass Spectrometry to Characterize a Novel PTM in the Escherichia coli Ribosomal Protein S12

摘要

To date, we identified 4 common proteins from SPA-S12 pull-downs and peptide pull-downs. We reproducibly identified these proteins to bind specifically to the S12 peptide. Both pull-down approaches compliment each other and strongly suggest that we have identified 4 proteins that interact with S12 at the site where the modification occurs. The next big question is how does the modification change the specificity of binding. The relative quantification approach will allow us to more effectively measure changes that occur as a result of increased or decreased binding affinity. Through collaborations with Jorge Heredia and Kenneth Kirk at NIDDK, beta-methylthio-aspartic acid has been synthesized and the corresponding modified peptide has been made.