PUB - Publikationen an der Universität Bielefeld

Benzoxazolinate is a rare bis-heterocyclic moiety that interacts with proteins and DNA and confers extraordinary bioactivities on natural products, such as C-1027. However, the biosynthetic gene responsible for the key cyclization step of benzoxazolinate remains unclear. Here, we show a putative acyl AMP-ligase responsible for the last cyclization step. We then use the enzyme as a probe for genome mining and discover that the orphan benzobactin gene cluster in entomopathogenic bacteria prevails across Proteobacteria and Firmicutes. It turns out thatPseudomonaschlororaphisproduces various benzobactins, whosebiosyntheses arehighlighted by a synergistic effect of two unclustered genes encoding enzymes on boosting benzobactin production;the formation of non-proteinogenic 2-hydroxymethylserine by a serine hydroxymethyltransferase; andthe types I and II NRPS architecture for structural diversity. Our findings reveal the biosynthetic potential of a widespread benzobactin gene cluster. © 2022 Wiley-VCH GmbH.