earticle

영어

Fucosyloligosaccharides, major components of human milk oligosaccharides (HMOs) are synthesized by fucosyltransferases (FTs), which transfer fucose from GDP-fucose to various acceptors such as galactose moiety (α1,2), or glucose/GlcNAc moiety (α1,3/α 1,4). Especially, 2’-fucosyllactose (2’-FL) and 3-fucosyllactose (3-FL) in HMO functions as prebiotics, immunomodulation, and anti-adehesion therapy against pathogens. For enzymatic in vitro production of 2’-FL and 3-FL, one-pot reaction from L-fucose have been studied with FKP (fucokinase/pyrophosphorylase) and 2’-FT/3-FT originated from H.pylori. To produce 2’-FL and 3-FL in large quantity using FTs, low expression level of soluble protein and low FT activity become the major hurdles for enzymatic reaction. For the improvement of soluble protein level, in the case of 2’-FT, codon optimization was done, and then fusion partners which are stress-responsive and highly stable E.coli proteins were introduced at N-terminal of 2’-FT. In the case of 3-FT, C-termial amino acids anchoring with membrane was truncated, and its sequence was optimized for E.coli codon usage. Using the improved soluble expression level of 2’-FT and 3-FT as a template, site-saturation mutagenesis was done with computer modeling and bioinformatic analysis. From the colorimetic screening, several muatants showing improved catalytic activity were selected and characterized.