• 제목/요약/키워드: BioInformatics

검색결과 580건 처리시간 0.029초

Glycosylation of Flavonoids with E. coli Expressing Glycosyltransferase from Xanthomonas campestris

  • Kim, Jeong-Ho;Kim, Bong-Gyu;Kim, Jae-Ah;Park, Young-Hee;Lee, Yoon-Jung;Lim, Yoong-Ho;Ahn, Joong-Hoon
    • Journal of Microbiology and Biotechnology
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    • 제17권3호
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    • pp.539-542
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    • 2007

  • Glycosyltransferase family 1 (UOT) uses small chemicals including phenolics, antibiotics, and alkaloids as substrates to have an influence in biological activities. A glycosyltransferase (XcGT-2) from Xanthomonas campestris was cloned and consisted of a 1,257 bp open reading frame encoding a 45.5 kDa protein. In order to use this for the modification of phenolic compounds, XcGT-2 was expressed in Escherichia coli as a glutathione S-transferase fusion protein. With the E. coli transformant expressing XcGT-2, biotransformation of flavonoids was carried out. Flavonoids having a double bond between carbons 2 and 3, and hydroxyl groups at both C-3' and C-4', were glycosylated and the glycosylation position was determined to be at the hydroxyl group of C-3', using nuclear magnetic resonance spectroscopy. These results showed that XcGT-2 regiospecifically transferred a glucose molecule to the 3'-hydroxyl group of flavonoids containing both 3' and 4'-hydroxyl groups.

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Quercetin Inhibits the 5-Hydroxytryptamine Type 3 Receptor-mediated Ion Current by Interacting with Pre-Transmembrane Domain I

  • Lee, Byung-Hwan;Jung, Sang-Min;Lee, Jun-Ho;Kim, Jong-Hoon;Yoon, In-Soo;Lee, Joon-Hee;Choi, Sun-Hye;Lee, Sang-Mok;Chang, Choon-Gon;Kim, Hyung-Chun;Han, YeSun;Paik, Hyun-Dong;Kim, Yangmee;Nah, Seung-Yeol
    • Molecules and Cells
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    • 제20권1호
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    • pp.69-73
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    • 2005

  • The flavonoid, quercetin, is a low molecular weight substance found in apple, tomato and other fruit. Besides its antioxidative effect, quercetin, like other flavonoids, has a wide range of neuropharmacological actions including analgesia, and motility, sleep, anticonvulsant, sedative and anxiolytic effects. In the present study, we investigated its effect on mouse 5-hydroxytryptamine type 3 ($5-HT_{3A}$) receptor channel activity, which is involved in pain transmission, analgesia, vomiting, and mood disorders. The $5-HT_{3A}$ receptor was expressed in Xenopus oocytes, and the current was measured with the two-electrode voltage clamp technique. In oocytes injected with $5-HT_{3A}$ receptor cRNA, quercetin inhibited the 5-HT-induced inward peak current ($I_{5-HT}$) with an $IC_{50}$ of $64.7{\pm}2.2{\mu}M$. Inhibition was competitive and voltage-independent. Point mutations of pre-transmembrane domain 1 (pre-TM1) such as R222T and R222A, but not R222D, R222E and R222K, abolished inhibition, indicating that quercetin interacts with the pre-TM1 of the $5-HT_{3A}$ receptor.

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