Crystal structure of UDP‐glucose:anthocyanidin 3‐O‐glucosyltransferase from Clitoria ternatea. (1st October 2013)

• Record Type: Journal Article
• Authors: Hiromoto, Takeshi; Honjo, Eijiro; Tamada, Taro; Noda, Naonobu; Kazuma, Kohei; Suzuki, Masahiko; Kuroki, Ryota
• Is Part Of: Journal of synchrotron radiation. Volume 20:Part 6(2013)
• Page Start: 894
• Page End: 898
• Publication Date: 2013-10-01
• Subjects: Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S0909049513020712
• Languages: English
• ISSNs: 0909-0495

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Flowers of the butterfly pea (<italic>Clitoria ternatea</italic>) 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 <italic>C. ternatea</italic> by UDP‐glucose:anthocyanidin 3‐<italic>O</italic>‐glucosyltransferase (<italic>Ct</italic>3GT‐A; AB185904). To elucidate the structure–function relationship of <italic>Ct</italic>3GT‐A, recombinant <italic>Ct</italic>3GT‐A was expressed in <italic>Escherichia coli</italic> and its tertiary structure was determined to 1.85 Å resolution by using X‐ray crystallography. The structure of <italic>Ct</italic>3GT‐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 <italic>Ct</italic>3GT‐A with that of the flavonoid glycosyltransferase <italic>Vv</italic>GT1 from red grape (<italic>Vitis vinifera</italic>) 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 <italic>Ct</italic>3GT‐A, but certain residues of <italic>Vv</italic>GT1 involved in binding kaempferol were found to be substituted in <italic>Ct</italic>3GT‐A. These findings are important for understanding the differentiation of acceptor‐substrate recognition in these two enzymes.</p> </abstract>