Two bacterial glycosphingolipid synthases responsible for the synthesis of glucuronosylceramide and α-galactosylceramide

Nozomu Okino, Mengbai Li, Qingjun Qu, Tomoko Nakagawa, Yasuhiro Hayashi, Mitsufumi Matsumoto, Yohei Ishibashi, Makoto Ito

研究成果: Contribution to journalArticle査読

2 被引用数 (Scopus)

抄録

Bacterial glycosphingolipids such as glucuronosylceramide and galactosylceramide have been identified as ligands for invariant natural killer T cells and play important roles in host defense. However, the glycosphingolipid synthases required for production of these ceramides have not been well-characterized. Here, we report the identification and characterization of glucuronosylceramide synthase (ceramide UDP-glucuronosyltransferase [Cer-GlcAT]) in Zymomonas mobilis, a Gram-negative bacterium whose cellular membranes contain glucuronosylceramide. On comparing the gene sequences that encode the diacylglycerol GlcAT in bacteria and plants, we found a homologous gene that is widely distributed in the order Sphingomonadales in the Z. mobilis genome. We first cloned the gene and expressed it in Escherichia coli, followed by protein purification using nickel–Sepharose affinity and gel filtration chromatography. Using the highly enriched enzyme, we observed that it has high glycosyltransferase activity with UDP-glucuronic acid and ceramide as sugar donor and acceptor substrate, respectively. Cer-GlcAT deletion resulted in a loss of glucuronosylceramide and increased the levels of ceramide phosphoglycerol, which was expressed in WT cells only at very low levels. Furthermore, we found sequences homologous to Cer-GlcAT in Sphingobium yanoikuyae and Bacteroides fragilis, which have been reported to produce glucuronosylceramide and a-galactosylceramide, respectively. We expressed the two homologs of the cer-glcat gene in E. coli and found that each gene encodes Cer-GlcAT and Cer-galactosyltransferase, respectively. These results contribute to the understanding of the roles of bacterial glycosphingolipids in host–bacteria interactions and the function of bacterial glycosphingolipids in bacterial physiology.

本文言語英語
ページ(範囲)10709-10725
ページ数17
ジャーナルJournal of Biological Chemistry
295
31
DOI
出版ステータス出版済み - 7 31 2020

All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学

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