2013 Fiscal Year Final Research Report
Biogenesis process of quinohemoprotein aminedehydrogenase accompanying multi-step posttranslational modification reactions
| Project/Area Number |
23570135
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | Osaka University |
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Principal Investigator |
NAKAI Tadashi 大阪大学, 産業科学研究所, 助教 (00333344)
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| Co-Investigator(Kenkyū-buntansha) |
TANIZAWA Katsuyuki 大阪大学, 産業科学研究所, 招へい教授 (20133134)
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| Project Period (FY) |
2011 – 2013
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| Keywords | 翻訳後修飾 / 補酵素の生合成 / 結晶構造解析 / キノヘムプロテイン / ビルトイン型キノン補酵素 / ラジカルSAMタンパク質 / 分子内チオエーテル架橋 / 酵素触媒機構 |
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| Research Abstract |
Peptidyl built-in cofactors are produced by posttranslational modification of the cognate enzyme proteins, unlike ordinary cofactors which are mostly bio-synthesized from water soluble vitamins. In this study, we focused on a built-in quinone cofactor-containing enzyme, quinohemoprotein amine dehydrogenase (QHNDH) that contains cysteine tryptophyl quinone (CTQ). The structural genes encoding QHNDH in Gram-negative bacteria constitute a polycistronic operon together with several nearby genes, which are collectively termed qhp. (1) We have identified three peripheral genes, qhpFGR, that are also absolutely required for the QHNDH biogenesis. (2) We have analyzed the function of QhpE and revealed that QhpE is an extremely unusual protease that cleaves its substrate nearly in a disposable manner. (3) We have succeeded in in vitro formation of thioether cross-links using overproduced recombinant QhpD only if it is purified and handled under anaerobic conditions.
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