Figure 4.

Streptomyces sp. AD-3-6-derived nybomycins 2–5 within the context of the biosynthetic pathway put forth by Luzhetskyy and colleagues (black) and pseudonocardians previously reported by Zhang et al. (red; *only relative stereochemistry assigned). Proposed biosynthetic revisions based on the current study are highlighted (blue). Compounds in brackets are putative intermediates, and dashed arrows represent putative transformations with possible enzyme catalysts noted where possible. Metabolite 3 reported herein was previously proposed by Luzhetskyy et al. as a biosynthetic intermediate, whereas metabolite 5 and pseudonocardians were previously reported by Zhang et al.