著者

藤田 祐一 栗栖 源嗣

出版者

一般社団法人 日本生物物理学会

雑誌

生物物理 (ISSN:05824052)

巻号頁・発行日

vol.51, no.2, pp.066-071, 2011 (Released:2011-03-30)

参考文献数

25

被引用文献数

1

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Protochlorophyllide (Pchlide) reduction is the final step to make up the spectroscopic properties of chlorophyll a in biosynthesis of chlorophyll. During evolution, photosynthetic organisms have invented two structurally unrelated Pchlide reductases; light-dependent Pchlide reductase (LPOR) and light-independent (dark-operative) Pchlide reductase (DPOR). LPOR is an NADPH-dependent enzyme operating as a key enzyme for the light-dependent greening in angiosperms, and DPOR is a nitrogenase-like enzyme that allows gymnosperms, algae, cyanobacteria and photosynthetic bacteria to produce (bacterio)chlorophylls even in the dark. We will review recent major research progresses on Pchlide reductases, especially, crystallographic structure and proposed reaction mechanism of DPOR. Differential operation and evolutionary implications of these enzymes are also discussed.

著者

藤田 祐一

出版者

名古屋大学

雑誌

戦略的な研究開発の推進 戦略的創造研究推進事業 ALCA(先端的低炭素化技術開発) 技術領域

巻号頁・発行日

2010

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現在70億近くの人口を支える高収量の農業は、工業的窒素固定によって生産される人工窒素肥料に依存しています。ハーバー・ボッシュ法による工業的窒素固定は大量の化石燃料を消費するため、その過程での二酸化炭素排出量は莫大です。本研究開発では、限られた原核生物だけに分布する窒素固定酵素ニトロゲナーゼを植物や微細藻類など有用光合成生物に移入することで、窒素固定性作物作出の基盤技術の確立を目指します。

著者

村木 則文 栗栖 源嗣 野亦 次郎 藤田 祐一

出版者

日本結晶学会

雑誌

日本結晶学会誌 (ISSN:03694585)

巻号頁・発行日

vol.53, no.2, pp.113-118, 2011-04-30 (Released:2011-05-25)

参考文献数

16

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Dark-operative protochlorophyllide reductase (DPOR) catalyses the reduction of protochlorophyllide (Pchlide) to chlorophyllide a, which is a key step in the chlorophyll biosynthesis pathway. DPOR is a nitrogenase-like enzyme consisting of two components, BchL and BchNB, which are structurally related to nitrogenase NifH and NifDK, respectively. We determined the crystal structure of the catalytic component of DPOR, BchNB, in Pchlide-bound and Pchlide-free forms. BchNB has a novel FeS cluster (NB-cluster) coordinated uniquely by one aspartate and three cysteines. NB-cluster is located at the spatial position corresponding to an electron mediating FeS cluster, P-cluster, in nitrogenase NifDK. A Pchlide molecule found in the Pchlide-bound form is accommodated in the cavity surrounded by many hydrophobic residues. We propose a unique trans-specific reduction mechanism by comparison between the Pchlide-bound and the Pchlide-free forms. The spatial arrangement of the NB-cluster and Pchlide is almost identical to that of the P-cluster and FeMo-cofactor in nitrogenase NifDK, suggesting that a common architecture exists to reduce chemically stable multibonds of porphyrin and dinitrogen.