| Project/Area Number |
17591942
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional basic dentistry
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| Research Institution | Nagasaki University |
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Principal Investigator |
OKAMOTO Kuniaki Nagasaki University, Graduate School of Biomedical Sciences, Associate Professor, 大学院医歯薬学総合研究科, 助教授 (10311846)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Yuuzo Nagasaki University, Graduate School ofBiomedical Sciences, Professor, 大学院医歯薬学総合研究科, 教授 (20014128)
NISHISHITA Kazuhisa Nagasaki University, Gaduate School ofBiomedical Sciences, Research Associate, 大学院医歯薬学総合研究科, 助手 (20237697)
SAKAI Eiko Nagasaki University, Gradua Graduate School ofBiomecfical Sciences, Associate, 大学院医歯薬学総合研究科, 助手 (10176612)
NAKAYAMA Koji NagasaldUnivetsity, Graduate School of Biomedical Sciences, Professor, 大学院医歯薬学総合研究科, 教授 (80150473)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Arg-gingipain / cysteine proteinase / Lys-gingipain / periodontitis disease / Porphysomonas gingivalis / transport / periodontal disease / Porphyromonas gingivalis |
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| Research Abstract |
A lysine-specific cysteine proteinase (Lys-gingipain, Kgp) is a unique cysteine proteinase produced by Porphyromonas gingivalis, a major etiological bacterium of periodontal diseases, and is implicated in the virulence of this bacterium. Studies on its structural and functional properties, however, have been limited by the difficulty in obtaining a sufficient amount of the enzyme. Here we show the expression of catalytically active recombinant Kgp in a P.gingivalis Kgp-null mutant and the restoration of its functions by use of a shuttle plasmid vector stably existing in P.gingivalis. The Kgp-expressing mutant exhibited a similar catalytic activity to that of the wild-type strain. This mutant also restored the ability to form black-pigmented colonies on blood agar plates and to generate a 19-kDa hemoglobin receptor protein responsible for hemoglobin binding. Furthermore, to establish the active-site Cys residue and its importance in the bacterial black pigmentation, we constructed three Kgp mutants with changed potential active-site Cys residues. The cells expressing single mutant (C476A) showed the high Kgp activity and the black pigmentation. By contrast, the cells expressing single mutant (C477A) and the double mutant (C476A/C477A) exhibited neither Kgp activity nor black pigmentation. The results indicate that 477^<th> Cys residue is essential for Kgp activity and the black pigmentation of P.gingivalis.
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