徳島大学 教育・研究者情報データベース(EDB)

1. 川上 竜巳([徳島大学.大学院社会産業理工学研究部.生物資源産業学域.食料科学系.食料科学分野]/[徳島大学.生物資源産業学部])

   役割	任意
   貢献度	任意
   学籍番号	推奨

2. (英) Ohshida Tatsuya / (日) 大志田 達也

   役割	任意
   貢献度	任意
   学籍番号	推奨

3. 櫻庭 春彦

   役割	任意
   貢献度	任意
   学籍番号	推奨

4. 大島 敏久([九州大学])

   役割	任意
   貢献度	任意
   学籍番号	推奨

(英) A novel PLP-dependent Alanine/Serine racemase from the hyperthermophilic archaeon Pyrococcus horikoshii OT-3

(英) We recently identified and characterized a novel broad substrate specificity amino acidracemase (BAR) from the hyperthermophilic archaeon Pyrococcus horikoshii OT-3.Three genes, PH0782, PH1423, and PH1501, encoding homologs exhibiting about45% sequence identity with BAR were present in the P. horikoshii genome. In this study,we detected pyridoxal 50-phosphate (PLP)-dependent amino acid racemase activity inthe protein encoded by PH0782. The enzyme showed activity toward Ala, Ser, Thr,and Val, but the catalytic efficiency with Thr or Val was much lower than with Ala orSer. The enzyme was therefore designated Ala/Ser racemase (ASR). Like BAR, ASRwas highly stable at high temperatures and over a wide range of pHs, though itshexameric structure differed from the dimeric structure of BAR. No activity was detectedin K291A or D234A ASR mutants. This suggests that, as in Ile 2-epimerase (ILEP) fromLactobacillus buchneri JCM1115, these residues are involved in Schiff base formationand substrate interaction, respectively. Unlike BAR, enhanced ASR activity was notdetected in P. horikoshii cells cultivated in the presence of D-Ala or D-Ser. This is thefirst description of a PLP-dependent fold type I ASR in archaea.

1. (英) Ala racemase
2. (英) Ser racemase
3. (英) PLP-dependent enzyme
4. (英) Pyrococcus horikoshii
5. (英) hyperthermophilic archaea
6. (英) D-amino acid