Sequence alignment of SgcJ and its homologues and overall structure of SgcJ and NCS-Orf16. (a) Sequence alignment of SgcJ and its homologues from the seven known 9-membered enediyne biosynthetic gene clusters. Aligned residues are colored on the basis of the level of conservation. Yellow background with red character and cyan background with red character show the putative general base and acid, respectively. Red background with white character shows strict identity, red character similarity and blue frame similarity across groups. The alignment was created with MUSCLE54 and rendered with ESPript 3.0.55 (b) Ribbon diagram and structural alignment of the SgcJ and NCS-Orf16 monomers. SgcJ and NCS-Orf16 are shown in light blue and yellow, respectively. (c) Ribbon diagram of the SgcJ dimer. The two chains are colored in blue and light blue, respectively. The NCBI accession numbers for each of the proteins are: SgcJ (ALU98438), NCS-Orf16 (AAM77985), MdpJ (ABY66022), KedJ (AFV52149), SpoJ (WP028564083), CyaJ (AG0972300), and CynJ (AG097162).