Kozak Maciej
Department of Macromolecular Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
Biopolymers. 2006 Sep;83(1):95-102. doi: 10.1002/bip.20531.
Xylanase (endo-1,4-beta-xylanase; EC 3.2.1.8) is an enzyme that catalyzes the hydrolysis reaction of xylan. The structure of the xylanase II (XYNII) molecule from Trichoderma longibrachoatum (formerly Trichoderma reesei) in a solution and at different pH values has been studied by small- and wide-angle scattering of synchrotron radiation (SAXS-WAXS). Analysis of the radius of gyration that characterizes xylanase has confirmed the stability of the above enzyme structure (the radius of gyration varied from 1.65 to 1.74 nm). On the basis of the SAXS data, the low-resolution structure of the xylanase molecule in solution has been reconstructed by using ab initio methods and programs DALAI_GA and DAMMIN. The full SAXS-WAXS data set (0.15 > s > 9.5 nm(-1)) fed to the program GASBOR permitted us to construct a chain-like spatial distribution of a dummy residues model of the xylanase molecule. The shape of the model molecules is similar to that of xylanase molecule in the crystal and shows the characteristic asymmetry that makes the molecule to resemble a right hand.
木聚糖酶（内切-1,4-β-木聚糖酶；EC 3.2.1.8）是一种催化木聚糖水解反应的酶。利用同步辐射的小角和广角散射（SAXS-WAXS）研究了长枝木霉（原里氏木霉）中木聚糖酶II（XYNII）分子在溶液中和不同pH值下的结构。对表征木聚糖酶的回转半径的分析证实了上述酶结构的稳定性（回转半径在1.65至1.74 nm之间变化）。基于SAXS数据，使用从头算方法以及DALAI_GA和DAMMIN程序重建了溶液中木聚糖酶分子的低分辨率结构。输入到GASBOR程序中的完整SAXS-WAXS数据集（0.15 > s > 9.5 nm-1）使我们能够构建木聚糖酶分子虚拟残基模型的链状空间分布。模型分子的形状与晶体中的木聚糖酶分子相似，并显示出特征性的不对称性，使分子类似于右手。
