TY - JOUR
T1 - Kinetic studies on recombinant UDP-glucose
T2 - sterol 3-O-β-glycosyltransferase from Micromonospora rhodorangea and its bioconversion potential
AU - Hoang, Nguyen Huu
AU - Huong, Nguyen Lan
AU - Kim, Byul
AU - Park, Je Won
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea Grant (2015R1A2A2A01002524) funded by the Ministry of Science, ICT and Future Planning, and by the Grant (PJ011066) funded by the Next-Generation BioGreen21 program, Rural Development Administration.
Publisher Copyright:
© 2016, The Author(s).
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Kinetics of a recombinant uridine diphosphate-glucose: sterol glycosyltransferase from Micromonospora rhodorangea ATCC 27932 (MrSGT) were studied using a number of sterols (including phytosterols) as glycosyl acceptors. The lowest Km value and the highest catalytical efficiency (kcat/Km) were found when β-sitosterol was the glycosyl acceptor in the enzymatic reaction. In contrast to the enzyme’s flexibility toward the glycosyl acceptor substrate, this recombinant enzyme was highly specific to uridine diphosphate (UDP)-glucose as the donor substrate. Besides, the UDP-glucose-dependent MrSGT was able to attach one glucose moiety specifically onto the C-3 hydroxyl group of other phytosterols such as fucosterol and gramisterol, yielding stereo-specific fucosterol-3-O-β-d-glucoside and gramisterol-3-O-β-d-glucoside, respectively. Based on kinetic data obtained from the enzyme’s reactions using five different sterol substrates, the significance of the alkene (or ethylidene) side chains on the C-24 position in the sterol scaffolds was described and the possible relationship between the substrate structure and enzyme activity was discussed. This is the first report on the enzymatic bioconversion of the above two phytosteryl 3-O-β-glucosides, as well as on the discovery of a stereospecific bacterial SGT which can attach a glucose moiety in β-conformation at the C-3 hydroxyl group of diverse sterols, thus highlighting the catalytic potential of this promiscuous glycosyltransferase to expand the structural diversity of steryl glucosides.
AB - Kinetics of a recombinant uridine diphosphate-glucose: sterol glycosyltransferase from Micromonospora rhodorangea ATCC 27932 (MrSGT) were studied using a number of sterols (including phytosterols) as glycosyl acceptors. The lowest Km value and the highest catalytical efficiency (kcat/Km) were found when β-sitosterol was the glycosyl acceptor in the enzymatic reaction. In contrast to the enzyme’s flexibility toward the glycosyl acceptor substrate, this recombinant enzyme was highly specific to uridine diphosphate (UDP)-glucose as the donor substrate. Besides, the UDP-glucose-dependent MrSGT was able to attach one glucose moiety specifically onto the C-3 hydroxyl group of other phytosterols such as fucosterol and gramisterol, yielding stereo-specific fucosterol-3-O-β-d-glucoside and gramisterol-3-O-β-d-glucoside, respectively. Based on kinetic data obtained from the enzyme’s reactions using five different sterol substrates, the significance of the alkene (or ethylidene) side chains on the C-24 position in the sterol scaffolds was described and the possible relationship between the substrate structure and enzyme activity was discussed. This is the first report on the enzymatic bioconversion of the above two phytosteryl 3-O-β-glucosides, as well as on the discovery of a stereospecific bacterial SGT which can attach a glucose moiety in β-conformation at the C-3 hydroxyl group of diverse sterols, thus highlighting the catalytic potential of this promiscuous glycosyltransferase to expand the structural diversity of steryl glucosides.
KW - Catalytic promiscuity
KW - Fucosterol-3-O-β-d-glucoside
KW - Gramisterol-3-O-β-d-glucoside
KW - Kinetics
KW - UDP-glucose sterol glycosyltransferase
UR - http://www.scopus.com/inward/record.url?scp=84982747990&partnerID=8YFLogxK
U2 - 10.1186/s13568-016-0224-x
DO - 10.1186/s13568-016-0224-x
M3 - Article
AN - SCOPUS:84982747990
SN - 2191-0855
VL - 6
JO - AMB Express
JF - AMB Express
IS - 1
M1 - 52
ER -