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- Dao, Trong Tuan, et al.
(author)
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Resveratrol suppressed lps-induced cox-2 VIA miR-146a-5p inhibition in raw246.7 cells
- 2017
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In: Farmacia. - 0014-8237. ; 65:2, s. 214-218
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Journal article (peer-reviewed)abstract
- Trans-resveratrol (Res) is a well-known natural stilbene frequently found in grapes which have been reported to possess antioxidant, anti-cancer activities and inhibited COX-2 expression. MicroRNAs (miRNAs) are short endogenous non-coding RNAs involved in the regulation of mRNA stability and protein synthesis. In our research, resveratrol isolated from Vitis heyneana Roem. & Schult Vitis heyneana was observed to suppress lipopolysaccharides (LPS)-induced COX-2 expression in Raw264.7 cells in a dose dependent manner. Using qPCR it was revealed that LPS induced the expression of miR-25, miR- 125a, miR-125b, miR-146a-5p, miR-146a-3p and miR-455. However, we only observed miR-146a-5p expression significantly decreased in resveratrol compared to untreated-control group. In addition, resveratrol abrogated the effect of miR-146a-5p mimic induced-COX-2 expression in Raw264.7 cells. Taken together, this study demonstrated for the first time the involvement of miR-146a-5p in resveratrol inhibited LPS-induced COX-2 expression in Raw264.7 cells.
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- Ngo, Son Tung, et al.
(author)
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Distal Hydrophobic Loop Modulates the Copper Active Site and Reaction of AA13 Polysaccharide Monooxygenases
- 2022
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 126:39, s. 7567-7578
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Journal article (peer-reviewed)abstract
- Polysaccharide monooxygenases (PMOs) use a type-2 copper center to activate O2 for the selective hydroxylation of one of the two C-H bonds of glycosidic linkages. Our electron paramagnetic resonance (EPR) analysis and molecular dynamics (MD) simulations suggest the unprecedented dynamic roles of the loop containing the residue G89 (G89 loop) on the active site structure and reaction cycle of starch-active PMOs (AA13 PMOs). In the Cu(II) state, the G89 loop could switch between an open and closed conformation, which is associated with the binding and dissociation of an aqueous ligand in the distal site, respectively. The conformation of the G89 loop influences the positioning of the copper center on the preferred substrate of AA13 PMOs. The dissociation of the distal ligand results in the bending of the T-shaped core of the Cu(II) active site, which could help facilitate its reduction to the active Cu(I) state. In the Cu(I) state, the G89 loop is in the closed conformation with a confined copper center, which could allow for efficient O2 binding. In addition, the G89 loop remains in the closed conformation in the Cu(II)-superoxo intermediate, which could prevent off-pathway superoxide release via exchange with the distal aqueous ligand. Finally, at the end of the reaction cycle, aqueous ligand binding to the distal site could switch the G89 loop to the open conformation and facilitate product release.
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