Fig. 4. Phylogenetic analyses of A and C domains of the BGCs vif, cif, syf, jesQS, and jesMWU. (A) ML tree of sequences encoding A domains. A domains cluster according to their substrate specificities. The branch to phenylalanine-activating domains (jes-A19) was used to root the tree. (B) ML tree of sequences encoding C domains. C domains mainly cluster according to their functional categories (C starter, LCL and dual E/C domains) (C) Subtree of selected Leu-activating A domains. As expected, A domains in position A8 of the lipo-octapeptide BGC (cif, vif, syf) share a common ancestor suggesting a stable positioning within the assembly line. In contrast to this, A4 and A7 of each strain are more closely related to each other than to their common ancestor. This finding suggests up to three independent exchange events of A domains between position A4 and A7 in the lipo-octapeptide clusters. (D) Subtree of A domains of Ser-activating domains of JesQS and JesMWU.
