BiG-SCAPE sequence similarity network (SSN) and nocobactin-like subfamilies visualized in Cytoscape. (A) SSN (c = 0.5) of Nocardia spp. Each node represents one BGC identified by antiSMASH 4.0. Colors represent phylogenetic clades A to F and X. Clade-specific GCFs are highlighted. (B) SSN (c = 0.7) of nocobactin-like BGCs. Representative pathways of different subfamilies (I to IX). Two singletons (X and XI) are shown. Abbreviations: TE, thioesterase; KS, ketosynthase; PKS, polyketide synthase; NRPS, nonribosomal peptide synthetase; NMO, N-monooxygenase; NAT, N-acetyltransferase; NFT, N-formyltransferase; SHMT, serine hydroxymethyltransferase.