title: Cloning and characterization of a novel β-carotene hydroxylase gene from Lycium barbarum and its expression in Escherichia coli.
abstract: Lycium barbarum contains high levels of zeaxanthin, which is produced by the conversion of β-carotene into zeaxanthin. β-Carotene hydroxylase catalyzes this reaction. We cloned a cDNA (chyb) encoding β-carotene hydroxylase (Chyb) from the L. barbarum leaf. A 939-bp full-length cDNA sequence was determined with 3'-rapid amplification of cDNA end assay encoding a deduced Chyb protein (34.8 kDa) with a theoretical isoelectric point of 8.36. A bioinformatics analysis showed that the L. barbarum Chyb was located in the chloroplast. Further, to investigate the catalytic activity of the L. barbarum Chyb, a complementation analysis was conducted in Escherichia coli. The results strongly demonstrated that Chyb can catalyze β-carotene to produce zeaxanthin. Thus, this study suggests that L. barbarum β-carotene hydroxylase could be a means of zeaxanthin production by genetic manipulation in E. coli.
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China; College of Agronomy & Resources and Environment, Tianjin Agricultural University, Tianjin, 300384, People's Republic of China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Ji
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Zhaodi
authors.initials: Z
authors.lastname: Li
authors.forename: Jinjin
authors.initials: J
authors.lastname: Diao
authors.forename: Guangxia
authors.initials: G
authors.lastname: Wu
mesh_terms: D003001:Cloning, Molecular; D018076:DNA, Complementary; D004926:Escherichia coli; D018506:Gene Expression Regulation, Plant; D032305:Lycium / Q000201:enzymology / Q000235:genetics*; D006899:Mixed Function Oxygenases / Q000096:biosynthesis* / Q000235:genetics* / Q000302:isolation & purification; D065146:Zeaxanthins / Q000378:metabolism; D019207:beta Carotene / Q000235:genetics / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D065146:Zeaxanthins; D019207:beta Carotene; D006899:Mixed Function Oxygenases; C079232:beta-carotene hydroxylase
keywords: Lycium barbarum; carotenoids; zeaxanthin; β-carotene hydroxylase