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Single amino acid mutations of Medicago glycosyltransferase UGT85H2 enhance activity and impart reversibility
Author(s) -
Modolo Luzia V.,
Escamilla-Treviño Luis L.,
Dixon Richard A.,
Wang Xiaoqiang
Publication year - 2009
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2009.05.046
Subject(s) - biochanin a , kaempferol , medicago truncatula , biochemistry , chemistry , threonine , glycosyltransferase , amino acid , mutagenesis , biology , mutation , quercetin , enzyme , genetics , serine , gene , genistein , bacteria , daidzein , antioxidant , symbiosis
The glycosyltransferase UGT85H2 from Medicago truncatula catalyzes glucosylation of the (iso)flavonoids kaempferol and biochanin A. Structure‐based mutagenesis of UGT85H2 was carried out to explore the roles of amino acids involved in substrate binding. Substitution of Ile305 by threonine increased catalytic efficiency 37‐ or 19‐fold with kaempferol or biochanin A as acceptor, respectively. A point mutation V200E also dramatically improved the turnover rate and catalytic efficiency by 15‐fold for kaempferol and 54‐fold for biochanin A. More interestingly, this single mutation (V200E) conferred reversibility in the glycosyltransfer reaction, indicating that Glu200 is a key determinant for the deglycosylation function.