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ツゲ ヒデアキ
TSUGE HIDEAKI
津下 英明 所属 京都産業大学 生命科学部 先端生命科学科 職種 教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2003/01 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | Crystal structure and site-directed mutagenesis of enzymatic components from Clostridium perfringens iota-toxin |
| 執筆形態 | その他 |
| 掲載誌名 | JOURNAL OF MOLECULAR BIOLOGY |
| 出版社・発行元 | ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD |
| 巻・号・頁 | 325(3),pp.471-483 |
| 担当区分 | 筆頭著者,責任著者 |
| 著者・共著者 | H Tsuge,M Nagahama,H Nishimura,J Hisatsune,Y Sakaguch,Y Itogawa,N Katunuma,J Sakurai |
| 概要 | Iota-toxin from Clostridium perfringens type E is an ADP-ribosylating toxin (ADPRT) that ADP-ribosylates actin, which is lethal and dermonecrotic in mammals. It is a binary toxin composed of an enzymatic component (la) and a binding component (Ib). la ADP-ribosylates G-actin at arginine 177, resulting in the depolymerization of the actin cytoskeleton. Here, we report on studies of the structure-function relationship by the crystal structures of la complexed with NADH and NADPH (at 1.8 Angstrom and 2.1 Angstrom resolution, respectively) and mutagenesis that map the active residues. The catalytic C-domain structure was similar to that of Bacillus cereus vegetative insecticidal protein (VIP2), which is an insect-targeted toxin, except for the EXE loop region. However, a significant structural difference could be seen in the N-domain, which interacts with Ib, suggesting an evolutionary difference between mammalian-targeted and insect-targeted ADPRT. The high resolution structure analysis revealed specific NAD conformation (a ring-like conformation of nicotinamide mononucleotide (NMN)) supported by Arg295, Arg296, Asn335, Arg352 and Glu380. Additionally, the mutagenesis study showed that the residues Tyr251, Arg295, Glu301, Ser338, Phe349, Arg352 and Glu380, including a newly identified one, are essential for NAD+-glycohydrolase (NADase) activity. At least one residue, Glu378, is an essential residue for ADP-ribosyltransferase (ARTase), but not for NADase. Consequently, the structural feature and these mutagenesis findings suggest that the catalytic mechanism of Ia proceeds via an Sn1-type reaction. (C) 2003 Elsevier Science Ltd. All rights reserved. |
| DOI | 10.1016/S0022-2836(02)01247-0 |
| ISSN | 0022-2836 |