L. Zhou and J-Y. Wang contributed equally to this work.
The diffusible factor synthase XanB2 is a bifunctional chorismatase that links the shikimate pathway to ubiquinone and xanthomonadins biosynthetic pathways
Article first published online: 19 NOV 2012
© 2012 Blackwell Publishing Ltd
Volume 87, Issue 1, pages 80–93, January 2013
How to Cite
Zhou, L., Wang, J.-Y., Wang, J., Poplawsky, A., Lin, S., Zhu, B., Chang, C., Zhou, T., Zhang, L.-H. and He, Y.-W. (2013), The diffusible factor synthase XanB2 is a bifunctional chorismatase that links the shikimate pathway to ubiquinone and xanthomonadins biosynthetic pathways. Molecular Microbiology, 87: 80–93. doi: 10.1111/mmi.12084
- Issue published online: 19 DEC 2012
- Article first published online: 19 NOV 2012
- Accepted manuscript online: 31 OCT 2012 11:50PM EST
- Manuscript Accepted: 26 OCT 2012
- National Natural Science Foundation of China. Grant Number: 31272005
- Returned Scholars from Shanghai Jiao Tong University. Grant Number: WS3107208008
- China Postdoctoral Science Foundation. Grant Number: 2011M500770
Vol. 90, Issue 2, 456, Article first published online: 9 OCT 2013
The diffusible factor synthase XanB2, originally identified in Xanthomonas campestris pv. campestris (Xcc), is highly conserved across a wide range of bacterial species, but its substrate and catalytic mechanism have not yet been investigated. Here, we show that XanB2 is a unique bifunctional chorismatase that hydrolyses chorismate, the end-product of the shikimate pathway, to produce 3-hydroxybenzoic acid (3-HBA) and 4-HBA. 3-HBA and 4-HBA are respectively associated with the yellow pigment xanthomonadin biosynthesis and antioxidant activity in Xcc. We further demonstrate that XanB2 is a structurally novel enzyme with three putative domains. It catalyses 3-HBA and 4-HBA biosynthesis via a unique mechanism with the C-terminal YjgF-like domain conferring activity for 3-HBA biosynthesis and the N-terminal FGFG motif-containing domain responsible for 4-HBA biosynthesis. Furthermore, we show that Xcc produces coenzyme Q8 (CoQ8) via a new biosynthetic pathway independent of the key chorismate-pyruvate lyase UbiC. XanB2 is the alternative source of 4-HBA for CoQ8 biosynthesis. The similar CoQ8 biosynthetic pathway, xanthomonadin biosynthetic gene cluster and XanB2 homologues are well conserved in the bacterial species within Xanthomonas, Xylella, Xylophilus, Pseudoxanthomonas, Rhodanobacter, Frateuria, Herminiimonas and Variovorax, suggesting that XanB2 may be a conserved metabolic link between the shikimate pathway, ubiquinone and xanthomonadin biosynthetic pathways in diverse bacteria.