The understanding of the biosynthetic logic of nonlinear nonribosomal peptide synthetases (NRPSs) provides potentially valuable tools for the engineering of diverse NRPs. In their Research Article on page 19766, Sun-Shin Cha, Dong-Chan Oh, Yeo Joon Yoon et al. elucidate the unprecedented features of a NRPS assembly line from marine Streptomyces that involves the shuttling of amino acids from two stand-alone adenylation (A)–thiolation (T) didomain modules to the iteratively operating condensation (C)–T didomain by two type II thioesterases (TEs).