ジャーナル: J Mol Biol / 年: 2012 タイトル: Structural analysis of Chi1 Chitinase from Yen-Tc: the multisubunit insecticidal ABC toxin complex of Yersinia entomophaga. 著者: Jason N Busby / Michael J Landsberg / Robert M Simpson / Sandra A Jones / Ben Hankamer / Mark R H Hurst / J Shaun Lott / 要旨: Yersinia entomophaga MH96 is a native New Zealand soil bacterium that secretes a large ABC-type protein toxin complex, Yen-Tc, similar to those produced by nematode-associated bacteria such as ...Yersinia entomophaga MH96 is a native New Zealand soil bacterium that secretes a large ABC-type protein toxin complex, Yen-Tc, similar to those produced by nematode-associated bacteria such as Photorhabdus luminescens. Y. entomophaga displays an exceptionally virulent pathogenic phenotype in sensitive insect species, causing death within 72 h of infection. Because of this phenotype, there is intrinsic interest in the mechanism of action of Yen-Tc, and it also has the potential to function as a novel class of biopesticide. We have identified genes that encode chitinases as part of the toxin complex loci in Y. entomophaga MH96, P. luminescens, Photorhabdus asymbiotica and Xenorhabdus nematophila. Furthermore, we have shown that the secreted toxin complex from Y. entomophaga MH96 includes two chitinases as an integral part of the complex, a feature not described previously in other ABC toxins and possibly related to the severe disease caused by this bacterium. We present here the structure of the Y. entomophaga MH96 Chi1 chitinase, determined by X-ray crystallography to 1.74 Å resolution, and show that a ring of five symmetrically arranged lobes on the surface of the Yen-Tc toxin complex structure, as determined by single-particle electron microscopy, provides a good fit to the Chi1 monomer. We also confirm that the isolated chitinases display endochitinase activity, as does the complete toxin complex.
解像度: 1.74→75.27 Å / Cor.coef. Fo:Fc: 0.968 / Cor.coef. Fo:Fc free: 0.948 / SU B: 2.407 / SU ML: 0.077 / 交差検証法: THROUGHOUT / ESU R Free: 0.11 / 立体化学のターゲット値: MAXIMUM LIKELIHOOD / 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS
Rfactor
反射数
%反射
Selection details
Rfree
0.20989
5541
5 %
RANDOM
Rwork
0.16452
-
-
-
all
0.16678
104841
-
-
obs
0.16678
104841
96.88 %
-
溶媒の処理
イオンプローブ半径: 0.8 Å / 減衰半径: 0.8 Å / VDWプローブ半径: 1.4 Å / 溶媒モデル: MASK