Cloning and Characterization of the Zeaxanthin Glucosyltransferase Gene (crtX) from the Astaxanthin-Producing Marine Bacterium, Paracoccus haeundaensis

Zeaxanthin glucosyltransferase (CrtX) mediates the formation of zeaxanthin to zeaxanthin diglucoside. Here, we report cloning of the crtX gene responsible for zeaxanthin diglucoside biosynthesis from Paracoccus haeundaensis and the production of the corresponding carotenoids in transformed cells carrying this gene. An expression plasmid containing the crtX gene (pSTCRT-X) was constructed, and Escherichia coli cells containing this plasmid produced the recombinant protein of approximately 46 kDa. Biosynthesis of zeaxanthin diglucoside was obtained when the plasmid pSTCRT-X was co-transformed into E. coli containing the pET-44a(+)-CrtEBIYZ carrying crtE, crtB, crtI, crtY, and crtZ genes required for zeaxanthin beta-D-diglucoside biosynthesis.