Characterization of NRPSs. a) A domain activities of PacP, PacU and PacW. NE, no enzyme; DABA, diaminobutyric acid; DAP, diaminopropionate; m-Tyr, meta-Tyrosine (DL). One hundred percent relative activity for l-2,3-DAP, l-Ala and m-Tyr-dependent exchange corresponds to 282k, 70k and 141k cpm respectively. b) Autoradiograph of one SDS-PAGE gel illustrating the covalent loading of 14C-labeled substrate (highlighted in red). Enzymes and substrates used in each lane are indicated in the table (highlighted in grey).