The astaxanthin dideoxyglycoside biosynthesis pathway in Sphingomonas sp. PB304

Se Hyeuk Kim, Jin Ho Kim, Bun Yeol Lee, Pyung Cheon Lee

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

A major carotenoid in Sphingomonas sp. PB304, originally isolated from a river in Daejon City, South Korea, was identified as astaxanthin dideoxyglycoside. Gene clusters encoding the astaxanthin dideoxyglycoside biosynthetic enzymes were identified by screening Sphingomonas sp. PB304 fosmid libraries using degenerate probes that harbor highly conserved sequences from the Sphigomonas elodea-derived crtI and Nostoc sp. PCC 7120-dervied crtW genes. Selected positive gene clusters were fully sequenced and annotated, revealing genes encoding six putative carotenogenic enzymes: phytoene synthase (CrtB), phytoene desaturase (CrtI), lycopene cyclase (CrtY), carotene hydroxylase (CrtZ), carotene ketolase (CrtW), and glycosyltransferase (CrtX). All of the carotenogenic enzymes, except for CrtX, were functional in the recombinant host Escherichia coli expressing synthetic carotenogenic modules from Pantoea agglomerans. CrtX did not take up UDP-glucose or GDP-fucose as sugar substrates during the in vitro reaction. Although no direct experimental evidence was obtained for the function of Sphingomonas sp. PB304 CrtX, it can be categorized as a putative deoxyglycosyltransferase based on the presence of astaxanthin dideoxyglycoside in Sphingomonas sp. PB304, a putative corresponding gene in the carotenoid biosynthetic gene cluster, and high amino acid sequence homology to the existing glycosyltransferases. Therefore, we propose that astaxanthin dideoxyglycoside can be synthesized in Sphingomonas sp. PB304 via sequential reactions of six pathway enzymes, including CrtX on the phytoene intermediate.
Original languageEnglish
JournalApplied Microbiology and Biotechnology
Volume98
Issue number24
Pages (from-to)9993-10003
ISSN0175-7598
DOIs
Publication statusPublished - 2014

Keywords

  • HASH(0x49d6660)
  • Carotenoid
  • Sphingomonas
  • Astaxanthin dideoxyglycoside
  • Glycosyltransferase

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