@article{oai:nagasaki-u.repo.nii.ac.jp:00015236,
 author = {Ishida, Yutaka and Hu, Jinping and Sakai, Eiko and Kadowaki, Tomoko and Yamamoto, Kenji and Tsukuba, Takayuki and Kato, Yuzo and Nakayama, Koji and Okamoto, Kuniaki},
 issue = {6},
 journal = {Archives of oral biology},
 month = {Jun},
 note = {Porphyromonas gingivalis, a major etiological bacterium of periodontal diseases, produces a unique lysine-specific cysteine proteinase (Lys-gingipain, Kgp) implicated in the virulence of this organism. Our observations show the expression of a catalytically active recombinant Kgp in a P. gingivalis Kgp-null mutant and the restoration of its functions by the use of a shuttle plasmid vector stable 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 haemoglobin receptor protein responsible for haemoglobin binding. In order to establish the importance of the active-site Cys residue and elucidate its role in bacterial black pigmentation we constructed three Kgp mutants with changed potential active-site Cys residues. The cells expressing a single mutation (C476A) showed the high Kgp activity and the black pigmentation. In contrast, the cells expressing the single mutant (C477A) and the double mutant (C476A/C477A) exhibited neither Kgp activity nor black pigmentation. These results indicate that the 477th Cys residue is essential for both the Kgp activity and the black pigmentation of P. gingivalis., 長崎大学学位論文 学位記番号:博（医歯薬）甲第139号 学位授与年月日:平成20年2月27日, Archives of oral biology, 53(6), pp.538-544; 2008},
 pages = {538--544},
 title = {Determination of active site of lysine-specific cysteine proteinase (Lys-gingipain) by use of a Porphyromonas gingivalis plasmid system.},
 volume = {53},
 year = {2008}
}