earticle

영어

Guanosine-5’-diphosphate (GDP)-L-fucose is an activated nucleotide sugar form of L-fucose, which plays an important role in a wide range of biological functions such as immune response and prevention of pathogen infection. In our previous study, overexpression of GDP-D-mannose 4,6-dehydratase (Gmd) and GDP-4-keto-6-deoxymannose 3,5-epimerase/4-reductase (WcaG) catalyzing de novo GDP-L-fucose biosynthesis led to high production of GDP-L-fucose in
recombinant Escherichia coli. In this study, the effects of the GDP-D-mannose, a key intermediate of GDP-L-fucose, was investigated by overexpression of GDP-D-mannose metabolic enzymes such as mannose-6-phosphate isomerase (ManA), phosphomannomutase (ManB), mannose-1-phosphate guanyltransferase (ManC). A maximum GDP-L-fucose concentration of 170.3±2.33 mg/L was achieved in a glucose-limited fed-batch fermentation of the recombinant E. coli BL21star(DE3) overexpressing ManB, ManC, Gmd and WcaG. The additional overexpression of mannose-6-phosphate isomerase (ManA) reduced GDP-L-fucose concentration to 83.3±4.24 mg/L, which might be due to the limitation of protein synthesis capacity in the host cell overexpressing themultiple genes involved in GDP-L-fucose synthesis. As a result, the amplification of the genes involved in the de novo pathway and GDP-D-mannose synthesis increased GDP-L-fucose concentration in recombinant E. coli by a 4.4-fold compared with the control strain overexpressing the gmd and wcaG genes only.