The lipocalin signature of violaxanthin de-epoxidase(VDE) from camellia sinensis was found in Swiss-Prot protein database. Gly(GGG) and Trp(TGG), the most conserved sites, in lipocalin signature were site-mutated to Leu(TTG) and Tyr(TAG), respectively, by using over-lap extension. The expression plasmids, pET-32a/G��L and pET-32a/W��Y, were expressed in E.coli BL21trxB(DE3) by IPTG mduction, then the expressed products were purified by Talon Metal Affinity Resin and determined by bio-activity assay. The results showed that the molecular mass of expressed protein was 5.89 kD as expected, and the amount of expression accounted for 45% of the total bacterial protein. Compared with the wild type VDE of camellia sinensis, the bio-activity of G��L mutant or W��Y was very low. It was demonstrated that lipocalin signature was one of the most active domains in VDE.
.Site-directed Mutation of Violaxanthin De-epoxidase from Tea Plant (Camellia sinensis) in vitro and Expression, Bio-activity Assay of the Mutants [J] Chinese Journal of Biochemistry and Molecular Biol, 2004,V20(01 ): 73-73