- Identification of rice Os4BGlu13 as a β-glucosidase which hydrolyzes gibberellin A4 1-O-β-d-glucosyl ester, in addition to tuberonic acid glucoside and salicylic acid derivative glucosides
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Abstract Gibberellin 1-O-β-d-glucose ester hydrolysis activity has been detected in rice seedling extracts, but no enzyme responsible for this activity has ever been purified and identified. Therefore, gibberellin A4 glucosyl ester (GA4-GE) β-d-glucosidase activity was purified from ten-day rice seedling stems and leaves. The family 1 glycoside hydrolase Os4BGlu13 was identified in the final purification fraction. The Os4BGlu13 cDNA was amplified from rice seedlings and expressed as an N-terminal thioredoxin-tagged fusion protein in Escherichia coli. The purified recombinant Os4BGlu13 protein (rOs4BGlu13) had an optimum pH of 4.5, for hydrolysis of p-nitrophenyl β-d-glucopyranoside (pNPGlc), which was the best substrate identified, with a kcat/Km of 637 mMmM-1 -1. rOs4BGlu13 hydrolyzed helicin best among natural glycosides tested (kcat/K m of 74.4 mM-1 -1). Os4BGlu13 was previously designated tuberonic acid glucoside (TAG) β-glucosidase (TAGG), and here the kcat/Km of rOsBGlu13 for TAG was 6.68 mM-1 -1, while that for GA4-GE was 3.63 mM-1 -1 and for salicylic acid glucoside (SAG) is 0.88 mM-1 -1. rOs4BGlu13 also hydrolyzed oligosaccharides, with preference for short β-(1 → 3)-linked over β-(1 → 4)-linked glucooligosaccharides. The enzymatic data suggests that Os4BGlu13 may contribute to TAG, SAG, oligosaccharide and GA4-GE hydrolysis in the rice plant, although helicin or a similar compound may be its primary target.
- Hua, Yanling,Ekkhara, Watsamon,Sansenya, Sompong,Srisomsap, Chantragan,Roytrakul, Sittiruk,Saburi, Wataru,Takeda, Ryosuke,Matsuura, Hideyuki,Mori, Haruhide,Ketudat Cairns, James R.
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- Stereoselective synthesis of epi-jasmonic acid, tuberonic acid, and 12-oxo-PDA
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epi-Jasmonic acid (epi-JA) and tuberonic acid (TA) were synthesized from the key aldehyde, all cis-2-(2-hydroxy-5-vinylcyclopentyl)acetaldehyde (14), which was in turn prepared stereoselectively from the (1R)-acetate of 4-cyclopentene-1,3-diol (10) through SN2-type allylic substitution with CH2CHMgBr followed by Mitsunobu inversion, Eschenmoser-Claisen rearrangement, and regioselective Swern oxidation of the corresponding bis-TES ether (13). Wittig reaction of the aldehyde 14 with [Ph3P(CH 2)Me]+Br- followed by oxidation afforded epi-JA (3) stereoselectivity over the trans isomer. Similarly, TA (5) was synthesized. Furthermore, the above findings were applied successfully to improve the total efficiency of the previous synthesis of 12-oxo-PDA (1).
- Nonaka, Hisato,Ogawa, Narihito,Maeda, Noriaki,Wang, Yong-Gang,Kobayashi, Yuichi
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body text
p. 5212 - 5223
(2010/12/25)
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- Phenolic glycosides from berries of Pimenta dioica
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Four new phenolic glycosides, (2-hydroxy-3-methoxy-5-allyl)phenyl β-D-(6-O-E-sinapoyl)glucopyranoside (1), (1′ R,5′R)-5-(5- carboxymefhyl-2-oxocyclopentyl)-3Z-pentenyl β-D-(6-O-galloyl) glucopyranoside (2), (5)-α-terpinyl [α-L-(2-O-galloyl) arabinofuranosyl]-(l→6)-β-D-glucopyranoside (3), and (R)-a-terpinyl [α-L-(2-O-galloyl)arabinofuranosyl]-(l→6)-β-D-glucopyranoside (4), were isolated from the berries of Pimenta dioica together with eight known flavonoids. The structures of 1-4 were elucidated on the basis of MS and NMR data and enzymatic hydrolysis. All four glycosides showed radical-scavenging activity against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals.
- Kikuzaki, Hiroe,Miyajima, Yoshiko,Nakatani, Nobuji
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experimental part
p. 861 - 865
(2009/04/04)
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- Synthesis and bioactivity of potassium β-D-glucopyranosyl 12-hydroxy jasmonate and related compounds
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Albizzia saman, a leguminous plant, is known to open its leaves in the daytime and sleep at night with the leaves folded. β-D-Glucopyranosyl 12-hydroxyjasmonate (1) was isolated as an endogenous chemical factor controlling this leafmovement. We developed a concise synthesis of optically pure (-)-1 in 9 steps from (+)-2 with a total yield of 58%. Similarly, such analogs of 1 as epi-LCF (13), enantiomer (14), and galactoside (19) were synthesized for a structure activity relationship (SAR) study. The results of this SAR study strongly suggest that the mechanism for the leaf-closing activity of 1 would be different from that of methyl jasmonate, and also suggest the involvement of a different kind of target protein which recognizes the trans-isomer of a jasmonate derivative.
- Nakamura, Yoko,Miyatake, Ryoji,Inomata, Sho,Ueda, Minoru
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experimental part
p. 2867 - 2876
(2009/04/11)
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- First total synthesis of tuberonic acid
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A vinyl group as an acetic acid side chain was attached to the optically active monoacetate of 4-cyclopentene-1,3-diol with CH2{double bond, long}CHMgBr, LiCl, and a CuCN catalyst to produce the SN2-type product, from which the full carbon skeleton of tuberonic acid was constructed through Mitsunobu inversion, Claisen rearrangement, and Wittig reaction. At the last stage, the THP protective group was removed with MgBr2 in Et2O. The diastereomeric ratio of tuberonic acid and the trans isomer was 92:8 by 1H NMR spectroscopy.
- Nonaka, Hisato,Wang, Yong-Gang,Kobayashi, Yuichi
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p. 1745 - 1748
(2008/02/05)
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- Synthesis of Jasmine Ketolactone
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The synthesis of jasmine ketolactone 3, a minor component of Italian jasmine oil, via the intramolecular Michael reaction is described.
- Kitahara,Takeshi,Iwamoto, Minoru,Takagi, Yoshikazu,Mori, Kenji,Matsui, Masanao
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p. 1731 - 1734
(2007/10/02)
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- STRUKTUR UND SYNTHESE VON N-(ACETOXY)-JASMONOYLPHENYLALANINMETHYLESTER AUS PRAXELIS CLEMATIDEA
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From Praxelis clematidea a phenylalanine derivative has been isolated, its structure being elucidated by spectroscopic methods and confirmed by synthesis.
- Bohlmann, Ferdinand,Wegner, Peter,Jakupovic, Jasmin,King, Robert M.
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p. 2537 - 2540
(2007/10/02)
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