Phosphopantetheinyl Transferase Catalyzed Site-Specific Protein Labeling with ADP Conjugated Chemical Probes

摘要

Protein posttranslational modification (PTM) plays an important role in expanding the structural and functional diversities of proteins in the cell. Among them, protein phosphopantetheinylation installs a 20 A long phosphopantetheinyl (Ppant) group derived from coenzyme A (CoA) 1 on a conserved Ser residue in the acyl carrier proteins (ACP) of fatty acid synthase and polyketide synthase (PKS), and peptidyl carrier proteins (PCP) of nonribosomal peptide synthetase (NRPS). The Ppant modification activates the carrier proteins for the attachment of biosynthetic intermediates during the enzymatic assembly of primary and secondary metabolites such as fatty acids, polyketides, and nonribosomal peptides (Figure 1A). In Bacillus subtilis, PCP modification by Ppant is catalyzed by Sfp phosphopantetheinyl transferase (PPTase), which shows significant substrate promiscuity with the chemical functionalities linked to the free thiol of CoA.