Sioxanthin, a novel glycosylated carotenoid, reveals an unusual subclustered biosynthetic pathway. (11th December 2014)

• Record Type: Journal Article
• Authors: Richter, Taylor K. S.; Hughes, Chambers C.; Moore, Bradley S.
• Is Part Of: Environmental microbiology. Volume 17:Number 6(2015:Jun.)
• Page Start: 2158
• Page End: 2171
• Publication Date: 2014-12-11
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1462-2920.12669
• Languages: English
• ISSNs: 1462-2912

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>Members of the marine actinomycete genus <italic>S</italic><italic>alinispora</italic> constitutively produce a characteristic orange pigment during vegetative growth. Contrary to the understanding of widespread carotenoid biosynthesis pathways in bacteria, <italic>S</italic><italic>alinispora</italic> carotenoid biosynthesis genes are not confined to a single cluster. Instead, bioinformatic and genetic investigations confirm that four regions of the <italic>S</italic><italic>alinispora tropica</italic> CNB‐440 genome, consisting of two gene clusters and two independent genes, contribute to the <italic>in vivo</italic> production of a single carotenoid. This compound, namely (2′<italic>S</italic>)‐1′‐(β‐D‐glucopyranosyloxy)‐3′, 4′‐didehydro‐1′, 2′‐dihydro‐φ, ψ‐caroten‐2′‐ol, is novel and has been given the trivial name 'sioxanthin'. Sioxanthin is a C<sub>40</sub>‐carotenoid, glycosylated on one end of the molecule and containing an aryl moiety on the opposite end. Glycosylation is unusual among actinomycete carotenoids, and sioxanthin joins a rare group of carotenoids with polar and non‐polar head groups. Gene sequence homology predicts that the sioxanthin biosynthetic pathway is present in all of the <italic>S</italic><italic>alinispora</italic> as well as other members of the family Micromonosporaceae. Additionally, this study's investigations of clustering of carotenoid biosynthetic genes in heterotrophic bacteria show that a non‐clustered genome arrangement is more common than previously suggested, with nearly half of the investigated genomes showing a non‐clustered architecture.</p> </abstract>