“…The first enzyme for the macrocyclization of RiPP peptide backbone was discovered in the biosynthesis of cyanobactins, specifically PatG in the patellamide pathway ( Koehnke et al., 2012 ; McIntosh et al., 2010 ). Cyanobactins are cyclic 6-to-8-amino acid peptides potentially containing multiple modifications, including heterocyclization, oxidation, and prenylation, which are catalyzed by heterocyclases (e.g., PatD), oxidases (e.g., ThcOx), N -terminal proteases (e.g., PatA), C -terminal proteases/cyclases (e.g., PatG), and prenyltransferases (e.g., PatF) ( Sardar et al., 2016 ). Natural cyanobactin analogues display promising biological activities ( Martins and Vasconcelos, 2015 ), e.g., cytotoxicity toward multiple-drug resistant cancers and protease inhibition.…”