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
言語種別 英語
発行・発表の年月 2007/01
形態種別 研究論文
査読 査読あり
標題 Structure of a hyperthermophilic archaeal homing endonuclease, I-Tsp061I: Contribution of cross-domain polar networks to thermostability
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 365(2),pp.362-378
担当区分 最終著者,責任著者
著者・共著者 Hitoshi Nakayama,Tatsuro Shimamura,Takahito Imagawa,Nobuaki Shirai,Takashi Itoh,Yoshihiko Sako,Masashi Miyano,Haruhiko Sakuraba,Toshihisa Ohshima,Norimichi Nomura,Hideaki Tsuge
概要 A novel LAGLIDADG-type homing endonuclease (HEase), I-TspO61I, from the hyperthermophilic archaeon Thermoproteus sp. IC-061 16 S rRNA gene (rDNA) intron was characterized with respect to its structure, catalytic properties and thermostability. It was found that I-Tsp061I is a HEase isoschizomer of the previously described I-PogI and exhibits the highest thermostability among the known LAGLIDADG-type HEases. Determination of the crystal structure of I-Tsp061I at 2.1 A resolution using the multiple isomorphous replacement and anomalous scattering method revealed that the overall fold is similar to that of other known LAGLIDADG-type HEases, despite little sequence similarity between I-TspO61I and those HEases. However, I-Tsp061I contains important cross-domain polar networks, unlike its mesophilic counterparts. Notably, the polar network Tyr6-Asp104-His180-107O-HOH12-104O-Asn177 exists across the two packed a-helices containing both the LAGLIDADG catalytic motif and the GxxxG hydrophobic helix bundle motif. Another important structural feature is the salt-bridge network Asp29-Arg31-GIu182 across N and C-terminal domain interface, which appears to contribute to the stability of the domain/domain packing. On the basis of these structural analyses and extensive mutational studies, we conclude that such cross-domain polar networks play key roles in stabilizing the catalytic center and domain packing, and underlie the hyperthermostability of T-Tsp061I. (c) 2006 Published by Elsevier Ltd.
DOI 10.1016/j.jmb.2006.09.066
ISSN 0022-2836