Aryl Polyenes, a Highly Abundant Class of Bacterial Natural Products, Are Functionally Related to Antioxidative Carotenoids

TLDR

Aryl polyenes are bacterial pigments structurally similar to carotenoids, with a widespread biosynthetic gene cluster that yields four distinct pigment classes across diverse bacteria. The authors characterized the aryl polyene/dialkylresorcinol hybrid pigments from *Variovorax paradoxus* B4 using HPLC‑UV‑MS, MALDI‑MS, and NMR. These pigments confer oxidative stress protection to the bacterium, and genomic analysis reveals a complementary distribution of aryl polyene and carotenoid biosynthetic genes among bacteria.

Abstract

Abstract Bacterial pigments of the aryl polyene type are structurally similar to the well‐known carotenoids with respect to their polyene systems. Their biosynthetic gene cluster is widespread in taxonomically distant bacteria, and four classes of such pigments have been found. Here we report the structure elucidation of the aryl polyene/dialkylresorcinol hybrid pigments of Variovorax paradoxus B4 by HPLC‐UV‐MS, MALDI‐MS and NMR. Furthermore, we show for the first time that this pigment class protects the bacterium from reactive oxygen species, similarly to what is known for carotenoids. An analysis of the distribution of biosynthetic genes for aryl polyenes and carotenoids in bacterial genomes is presented; it shows a complementary distribution of these protective pigments in bacteria.