More rapid evaluation of biomacromolecular crystals for diffraction experiments

回折実験のための生体高分子結晶のより迅速な評価

新井 栄揮; 茶竹 俊行; 鈴木 喜大*; 水野 洋*; 新村 信雄

Arai, Shigeki; Chatake, Toshiyuki; Suzuki, Nobuhiro*; Mizuno, Hiroshi*; Niimura, Nobuo

生体高分子の結晶品質の評価に用いられてきたパラメータ(R-merge, I/sigma, 最大分解能, mosaicity)は回折実験の条件に強く依存する。本論文ではrelative Wilson plot法の特徴について述べ、このプロットから得られるoverall B-factorが蛋白質結晶のcharacterizationに適していることを説明する。relative Wilson plotの例として、B型DNA十量体d(CCATTAATGG),DsrD蛋白質,鶏卵白リゾチームの評価結果を示す。B型DNAやDsrD蛋白質の結晶品質は、結晶化相図上の条件に強く依存することが明らかになった。一方、鶏卵白リゾチームの結晶品質は、結晶化相図上の条件にほとんど依存しないことが判明した。

The parameters used for evaluating biomacromolecular crystal quality (, /(), maximum resolution and mosaicity) strongly depend on the diffraction experimental conditions. In this paper we describe the distinctive features of the relative Wilson plot method, and we show that the overall B-factor obtained from this plot is given as a more appropriate to characterize protein crystals. The relative Wilson plot has been applied to the characterization of crystals of a B-DNA decamer d(CCATTAATGG), and crystals of the proteins DsrD (dissimilatory sulfite reductase D) and hen egg-white lysozyme (HEWL) which we have studied by neutron diffraction. We have found that the crystal qualities of the B-DNA decamer and DsrD significantly depend on the regions of the crystallization phase diagram from which samples were taken. However, in the case of HEWL, crystal quality appears to be independent on the region of the crystallization phase diagram.