Site-directed mutagenesis of a possible type I copper ligand of bilirubin oxidase; a Met467Gln mutant shows stellacyanin-like properties

フォーマット:

論文

責任表示:

Shimizu, Atsushi ; Sasaki, Takashi ; Kwon, Jung Hee ; Odaka, Akito ; Satoh, Takanori ; Sakurai, Nobuhiko ; Sakurai, Takeshi ; Yamaguchi, Shotaro ; Samejima, Tatsuya

言語:

英語

出版情報:

日本生化学会 = Japanese Biochemical Society, 1999-01-01

著者名:

Shimizu, Atsushi

Sasaki, Takashi

Kwon, Jung Hee

Odaka, Akito

Satoh, Takanori

Sakurai, Nobuhiko

Sakurai, Takeshi

Yamaguchi, Shotaro

Samejima, Tatsuya

続きを見る

掲載情報:

Journal of Biochemistry

ISSN:

0021-924x      

巻:

125

通号:

4

開始ページ:

662

終了ページ:

668

バージョン:

publisher

概要:

金沢大学理工研究域物質化学系<br />In our previous paper, we reported a mutant of recombinant Myrothecium verrucaria bilirubin oxidase, in which the Met467 residue was replaced by Gly. This mutant displayed a remarkable reduction in enzymatic activi … ty and an evident decrease in the intensity of the absorption band around 600 nm (type 1 charge transfer transition). In this study, we report the preparation of three Met467 mutants (Met467Gln, Met467His, and Met467Arg) and characterize their enzymatic activities, midpoint potentials, and absorption and ESR spectra. Met467His and Met467Arg show no enzymatic activity and a great reduction in the intensity of the absorption band around 600 nm. Furthermore, their ESR spectra show no type 1 copper signal, but only a type 2 copper signal; however, oxidation by ferricyanide caused the type 1 copper signal to appear. On the other hand, Met467Gln as expressed shows both type 1 and type 2 copper signals in its ESR spectrum, the type 1 copper atom parameters being very different from usual blue copper proteins but very similar to those of stellacyanin. The enzymatic activity of the Met467Gln mutant for bilirubin is quite low (0.3%), but the activity for potassium ferrocyanide is similar (130%) to that of the wild type enzyme. These results indicate that Met467 is important for characterizing the features of the type 1 copper of bilirubin oxidase. 続きを見る

URL:

http://hdl.handle.net/2297/16744