REGULATION IN BIOSYNTHESIS OF CHLOROPHYLL IN CHLOROPLAST OF CULTURED CELLS OF LIVERWORT

苔类培养细胞叶绿素生物合成的调控

• 批准号: 08660125
• 负责人: NABETA Kensuke
• 金额: $ 1.6万
• 依托单位: OBIHIRO UNIVERSITY OF AGRICULTURE AND VETERINARY MEDICINE
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08660125/
• 关键词: LIVERWORTS; HETEROSCYPHUS PLANUS; SUSPENSION CULTURED CELLS; BIOSYNTHESIS; NON-MEVALONATE PATHWAY; PHYTYL SIDE-CHAIN OF CHLOROPHYLL; CAROTENOIDS; beta-BARBATENE; Heteroscyphus planus; 培養細胞; 葉緑体; クロロフィル; フィトール

Chloroplastidic terpenoids were believed for long time to be biosynthesized via mevalonate utilizing pathway. They have, however, very recently been proven to be biosynthesized via non-mevalonate mediating pathway. The objectives of this research are to demonstrate a mechanism of preferential labelling in the formation of isoprenoids within chloroplasts of livewort and to prove a simultaneous operation of mevalonate utilizing pathway and non-mevalonate-mediating pathway. I also verified involvement of acetate assimilation in biosynthesis of chloroplastidic terpenoids.The ^2H- and ^<13>C-labelled acetate, glycerol and glucose were fed to the suspension cultures of H.planus to verify involvement of non-mevalonate pathway and acetate assimilation in the formation of chloroplastidic terpenoids. To elucidate the mechanism of the preferential labelling of the FPP-derived portion, we isolated chloroplasts from protoplasts which are prepared from cultured cells oh H.planus. and incubated with … More non-labelled, and ^3H and ^<14>C labelled mevalonate, isoprenyl diphosphate (IPP) and FPP.Labelling patterns of the phytyl side chain incorporating [6,6-^2H_2]-glucose and [2-^<13>C]-glycerol indicated that non-mevalonate pathway involves the biosynthesis of the phytyl side chain. Labelling patterns of the phytyl side chain incorporating labelled acetate demonstrate two important results, i.e. (1) intact acetate was decomposed prior to the formation of mevalonate. Acetate was reformed either from two methyl carbons or two carboxy carbon. Mevalonate was formed from the reformed acetate, and (2) these findings suggest that mevalonate was also formed in chloroplasts. And acetate was assimilated by a consecutive passages of TCA cycle, reductive pentose phosphate cycle and glycolic path way.Radioisotopically labelled FPP was effectively incorporated into chloroplasts and converted to geranylgeranyl moiety and phytyl moiety very rapidly, while labelled mevalonate was incorporated to these compounds to a less extent. These results indicated that chloroplasts can take in FPP directly (or indirectly) and then convert it to geranylgeranyl diphosphate (GGPP). While mevalonate might be incorporated into chloroplasts at very low level but it can be metabolized to GGPP within chloroplasts. They also indeed indicate that the preferential labelling of the FPP-derived portion was caused by direct (or indirect) uptake of FPP by chloroplasts. Less

叶绿体萜类化合物的生物合成一直被认为是通过甲羟戊酸代谢途径。然而，它们最近被证明是通过非甲羟戊酸介导的途径生物合成的。本研究的目的是证明一个机制，优先标记在叶绿体内的类异戊二烯的形成，并证明同时运作的甲羟戊酸利用途径和非甲羟戊酸介导的途径。另外，我还验证了乙酸同化作用参与叶绿体萜类化合物的生物合成，并将^2H-和^2C<13>-标记的乙酸、甘油和葡萄糖分别喂入悬浮培养的扁平线虫中，以验证非甲羟戊酸途径和乙酸同化作用参与叶绿体萜类化合物的形成。为了阐明的优先标记的FPP衍生部分的机制，我们分离叶绿体从原生质体制备的培养细胞OH H.并与 ...更多信息 非标记、^3H和^<14>C标记的甲羟戊酸、异戊二烯基二磷酸（IPP）和FPP.植基侧链掺入[6，6-^2H_2]-葡萄糖和[2-^<13>C]-甘油的标记模式表明非甲羟戊酸途径涉及植基侧链的生物合成。掺入标记乙酸酯的植基侧链的标记模式证明了两个重要结果，即（1）完整的乙酸酯在形成甲羟戊酸之前被分解。乙酸酯由两个甲基碳或两个羧基碳重整而成。甲羟戊酸由重组的乙酸盐形成，（2）这些发现表明甲羟戊酸也在叶绿体中形成。乙酸通过TCA循环、还原性戊糖磷酸循环和乙醇酸途径被同化，放射性同位素标记的FPP被有效地掺入叶绿体，并迅速转化为香叶基香叶基和植基，而标记的甲羟戊酸掺入这些化合物的程度较小。这些结果表明，叶绿体可以直接（或间接）吸收FPP，并将其转化为香叶基香叶基二磷酸（GGPP）。而甲羟戊酸可能以很低的水平掺入叶绿体，但它可以在叶绿体内代谢为GGPP。它们也确实表明，FPP衍生部分的优先标记是由叶绿体直接（或间接）摄取FPP引起的。少

项目成果

Kensuke Nabeta et.al.: "Biosynthesis of phytyl side-chain of chlorophyll a: apparent reutilization of carbon dioxide during acetate assimilation in biosynthesis of chloroplastidic isoprenoid.." Chem.Commun.(印刷中). (1998)

Kensuke Nabeta 等人：“叶绿素 a 植基侧链的生物合成：叶绿体类异戊二烯生物合成中乙酸同化过程中二氧化碳的明显再利用。”Chem.Commun.（出版中）。

Kensuke, Nabeta et.al.: "In vitro Biosynthesis of cadinanes by cell-free extracts of cultured cells of Heteroecyphus planus" J.Chem.Soc.Perkin Trans I. 2065-2070 (1997)

Kensuke, Nabeta 等人：“Heteroecyphus planus 培养细胞的无细胞提取物体外生物合成 cadinanes” J.Chem.Soc.Perkin Trans I. 2065-2070 (1997)

Kensuke Nabeta et.al.: "Biosynthesis of β-barbatene from ^<13>C-and ^2H-labelled acetate,mevalonate and glycerol" Chem.Commun.169-170 (1998)

Kensuke Nabeta等人：“从13C-和2H-标记的乙酸盐、甲羟戊酸和甘油生物合成β-barbatene”Chem.Commun.169-170(1998)

Kensuke, Nabeta et.al.: "Chlorophyll a and β-Carotene Syntheses from ^2H and ^<13>C labelled Mevalonates and ^<13>C Labelled Glvcine in Cultured Cells of Liverworts,Heterscyphus planus and Lophocolea" J.Chem.Soc.Perkin Trans I. 261-267 (1997)

Kensuke、Nabeta 等人：“在地钱、Heterscyphus planus 和 Lophocolea 的培养细胞中从 2H 和 13 C 标记的甲羟戊酸盐和 13 C 标记的甘氨酸合成叶绿素 a 和 β-胡萝卜素”，J.Chem。社会学会珀金翻译 I. 261-267 (1997)

鍋田 憲助: "イソペンテニルピロリン酸の新しい生合成経路" 化学と生物. 35. 430-431 (1997)

Kensuke Nabeta：“异戊烯基焦磷酸的新生物合成途径”化学与生物学 35. 430-431 (1997)。