title: Crystal structure of UDP-glucose:anthocyanidin 3-O-glucosyltransferase from Clitoria ternatea.
abstract: Flowers of the butterfly pea (Clitoria ternatea) accumulate a group of polyacylated anthocyanins, named ternatins, in their petals. The first step in ternatin biosynthesis is the transfer of glucose from UDP-glucose to anthocyanidins such as delphinidin, a reaction catalyzed in C. ternatea by UDP-glucose:anthocyanidin 3-O-glucosyltransferase (Ct3GT-A; AB185904). To elucidate the structure-function relationship of Ct3GT-A, recombinant Ct3GT-A was expressed in Escherichia coli and its tertiary structure was determined to 1.85 Å resolution by using X-ray crystallography. The structure of Ct3GT-A shows a common folding topology, the GT-B fold, comprised of two Rossmann-like β/α/β domains and a cleft located between the N- and C-domains containing two cavities that are used as binding sites for the donor (UDP-Glc) and acceptor substrates. By comparing the structure of Ct3GT-A with that of the flavonoid glycosyltransferase VvGT1 from red grape (Vitis vinifera) in complex with UDP-2-deoxy-2-fluoro glucose and kaempferol, locations of the catalytic His-Asp dyad and the residues involved in recognizing UDP-2-deoxy-2-fluoro glucose were essentially identical in Ct3GT-A, but certain residues of VvGT1 involved in binding kaempferol were found to be substituted in Ct3GT-A. These findings are important for understanding the differentiation of acceptor-substrate recognition in these two enzymes.
authors.affiliation: Quantum Beam Science Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hiromoto
authors.forename: Eijiro
authors.initials: E
authors.lastname: Honjo
authors.forename: Taro
authors.initials: T
authors.lastname: Tamada
authors.forename: Naonobu
authors.initials: N
authors.lastname: Noda
authors.forename: Kohei
authors.initials: K
authors.lastname: Kazuma
authors.forename: Masahiko
authors.initials: M
authors.lastname: Suzuki
authors.forename: Ryota
authors.initials: R
authors.lastname: Kuroki
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D001483:Base Sequence; D031292:Clitoria / Q000201:enzymology*; D018360:Crystallography, X-Ray; D017931:DNA Primers; D005964:Glucosyltransferases / Q000737:chemistry*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D014532:Uridine Diphosphate Glucose / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D017931:DNA Primers; D005964:Glucosyltransferases; D014532:Uridine Diphosphate Glucose
keywords: anthocyanidin; crystal structure; glucosylation; glucosyltransferase