2013 Fiscal Year Final Research Report
Dark-operative protochlorophyllide reductase and nitrogenase: common mechanism for reduction of stable multiple-bonds
| Project/Area Number |
23370020
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plant molecular biology/Plant physiology
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| Research Institution | Nagoya University |
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Principal Investigator |
FUJITA Yuichi 名古屋大学, 生命農学研究科, 准教授 (80222264)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH Shigeru 名古屋大学, 遺伝子実験施設, 名誉教授 (40108634)
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| Co-Investigator(Renkei-kenkyūsha) |
TAMIAKI Hitoshi 立命館大学, 薬学部, 教授 (00192641)
KURISU Genji 大阪大学, たんぱく質研究所, 教授 (90294131)
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| Project Period (FY) |
2011-04-01 – 2014-03-31
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| Keywords | ラジカル酵素 / 鉄硫黄クラスター / クロロフィル生合成 |
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| Research Abstract |
In final stages of biosynthesis of Chlorophylls (Chls), dark-operative protochlorophyllide (Pchlide) oxidoreductase (DPOR), a nitrogenase-like enzyme, reduces the C17=C18 double bond of Pchlide to form chlorophyllide, the direct precursor of Chl a. Crystallographic structure of DPOR suggested that the spatial arrangement of the proton donors determines the stereospecificity of the Pchlide reduction. In this study, reaction intermediates were trapped by blocking the proton transfer and they were detected by absorption and electron spin resonance spectroscopies. We proposed that the DPOR reaction consists of 1) generation of a Pchlide anion radical by a single electron transfer reaction from a [4Fe-4S]-cluster to Pchlide, 2) a second Pchlide neutral radical is formed by a single proton transfer, 3) a second electron transfer eliminates the Pchlide radical, and 4) a second proton transfer completes the reaction. DPOR is a unique radical enzyme with a structure common to nitrogenase.
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[Journal Article] An unexpectedly branched biosynthetic pathway for bacteriochlorophyll b capable of absorbing near-infrared light2013
Author(s)
Tsukatani, Y., Yamamoto, H., Harada, J., Yoshitomi, T., Nomata, J., Kasahara, M., Mizoguchi, T., Fujita, Y., Tamiaki, H
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Journal Title
Sci. Rep.
Volume: 3
Pages: 1217
DOI
Peer Reviewed
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