Functional Characterization and Protein Engineering of a Triterpene 3‐/6‐/2′‐
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‐Glycosyltransferase Reveal a Conserved Residue Critical for the Regiospecificity
We characterized the first plant cycloartane glycosyltransferase AmGT8 from A. membranaceus. Its mutants A394F, A394D, and T131V were discovered using semi-rational design, which showed specific 6-O, 3-O, and 2′-O glycosylation activities, respectively. This study uncovered a conservedresiduecritical for the regiospecificity of plant glycosyltransferases.
Triterpene glycosides of Astragalus and their genins XXXV. Cycloaraloside C from Astragalus amarus
作者:M. I. Isaev、N. K. Abubakirov
DOI:10.1007/bf00630078
日期:1990.11
A newtriterpene glycoside of the cycloartane series (cycloaraloside C) has been isolated from the roots of the plantAstragalus amarus Pall. (Leguminosae). Cycloaraloside C is a bioside of cyclosieversigenin including one D-glucose residue and one D-apiose residue. The structure of the glycoside has been shown on the basis of the chemical transformations and spectral characteristics as 20R,24S-epoxycycloartane-3β
Abstract A new triterpenoid glycoside, astrailienin A, was isolated from the roots of Astragalus iliensis. By heterogeneous acid hydrolysis an aglycone was obtained which was identified as cycloastragenol. On the basis of spectral analysis and chemical reactions, the structure of the new compound was assigned as the 3-O-[β-d -apio- d - furanosyl(1→2)]-β- d -glucopyranoside of cycloastragenol.