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The diffusible factor synthase XanB2 is a bifunctional chorismatase that links the shikimate pathway to ubiquinone and xanthomonadins biosynthetic pathways
Author(s) -
Zhou Lian,
Wang JiaYuan,
Wang Jianhe,
Poplawsky Alan,
Lin Shuangjun,
Zhu Bangshang,
Chang Changqing,
Zhou Tielin,
Zhang LianHui,
He YaWen
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12084
Subject(s) - shikimate pathway , biosynthesis , biochemistry , biology , dehydratase , phosphofructokinase 2 , xanthomonas campestris , atp synthase , metabolic pathway , shikimic acid , enzyme , gene
Summary The diffusible factor synthase XanB2 , originally identified in X anthomonas 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 Q 8 ( CoQ 8) via a new biosynthetic pathway independent of the key chorismate‐pyruvate lyase UbiC . XanB2 is the alternative source of 4‐ HBA for CoQ 8 biosynthesis. The similar CoQ 8 biosynthetic pathway, xanthomonadin biosynthetic gene cluster and XanB2 homologues are well conserved in the bacterial species within X anthomonas , X ylella , X ylophilus , P seudoxanthomonas , R hodanobacter , F rateuria , H erminiimonas and V ariovorax , suggesting that XanB2 may be a conserved metabolic link between the shikimate pathway, ubiquinone and xanthomonadin biosynthetic pathways in diverse bacteria.