title: Biochemical characterization of an isoform of GDP-D-mannose-4,6-dehydratase from Mortierella alpina.
abstract: OBJECTIVE
  To clarify the molecular mechanism of GDP-L-fucose biosynthesis in Mortierella alpina.
  
  
  RESULTS
  Analysis of the M. alpina genome suggests that there were two isofunctional GDP-D-mannose-4,6-dehydratase genes (GMD1 and GMD2) that have never been found in a microorganism before. GMD2 was expressed heterologously in Escherichia coli and purified to homogeneity. The addition of exogenous NAD(+) or NADP(+) was not essential for GMD2 activity. GMD2 may have considerable importance for GDP-L-fucose biosynthesis under nitrogen starvation. The transcriptional regulation of GMD1 may be more susceptible to GDP and GTP than that of GMD2. Significant changes were observed in the concentration of GDP-L-fucose (30 and 36 % inhibition respectively) and total fatty acids (18 and 12 % inhibition respectively) in M. alpina grown on GMD inhibitors medium, which suggests that GDP-L-fucose is functionally significant in lipid metabolism.
  
  
  CONCLUSIONS
  This is the first time that an isofunctional GDP-D-mannose-4,6-dehydratase has been characterized in a microorganism.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Hongchao
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Haiqin
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Zhennan
authors.initials: Z
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China. yqchen@jiangnan.edu.cn.|Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA. yqchen@jiangnan.edu.cn.
authors.forename: Yong Q
authors.initials: YQ
authors.lastname: Chen
mesh_terms: D003001:Cloning, Molecular / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D016681:Genome, Fungal; D006154:Guanosine Diphosphate Fucose / Q000096:biosynthesis*; D006836:Hydro-Lyases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D050356:Lipid Metabolism; D020094:Mortierella / Q000201:enzymology* / Q000235:genetics; D009584:Nitrogen / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D007527:Isoenzymes; D006154:Guanosine Diphosphate Fucose; D006836:Hydro-Lyases; C044971:GDPmannose 4,6-dehydratase; D009584:Nitrogen
keywords: Characterization; De novo pathway; GDP-D-mannose-4,6-dehydratase; GDP-L-fucose; Isoform; Mortierella alpina