Crystal structure of UDP-glucose: anthocyanidin 3-- glucosyltransferase from

チョウマメ花弁由来UDP-グルコース: アントシアニジン3--グルコシルトランスフェラーゼのX線結晶構造解析

廣本 武史; 本庄 栄二郎*; 玉田 太郎; 黒木 良太

Hiromoto, Takeshi; Honjo, Eijiro*; Tamada, Taro; Kuroki, Ryota

UDP-glucose: anthocyanidin 3--glucosyltransferase from (3GT-A; AB185904) is an enzyme that catalyses glucosyl transfer from UDP-glucose to anthocyanidins such as delphinidin, which is the first step of ternatin biosynthesis (Kogawa ., 2007). The recombinant wild-type enzyme was expressed in cells, purified to homogeneity and crystallized. The X-ray diffraction data set was collected at PF-BL6A using a crystal with a size of 0.05 0.05 0.5 mm, which belongs to the space group 2 with cell dimensions of = 50.2 , = 55.2 , = 86.2 and = 105.1 . The initial phase was solved by MR using the coordinates of a homologous glucosyltransferase GT1 from (PDB ID: 2C1Z) as a search model. The overall structure of 3GT-A shows a typical GT-B fold comprising two Rossmann-like // domains. The putative binding sites for UDP-glucose and delphinidin are located in a deep cleft between the N- and C-terminal domains. Structural homology searches by Dali server indicated that 3GT-A is similar to the other plant glucosyltransferases GT1 and UGT78G1 from with the RMS deviations of 1.9 (for 432 C atoms) and 2.0 (for 437 C atoms), respectively.