来自小麦胚芽的胰蛋白酶抑制剂I-2及其与胰蛋白酶复合物的结晶和初步X射线研究。
Crystallization and preliminary X-ray studies on the trypsin inhibitor I-2 from wheat germ and its complex with trypsin.
作者信息
Suzuki A, Kurasawa T, Tashiro C, Hasegawa K, Yamane T, Ashida T
机构信息
Department of Biotechnology, School of Engineering, Nagoya University, Japan.
出版信息
Acta Crystallogr D Biol Crystallogr. 1993 Nov 1;49(Pt 6):594-6. doi: 10.1107/S0907444993006134.
A Bowman-Birk type trypsin inhibitor I-2, M(r) = 14 000, 123 amino-acid residues, isolated from wheat germ, and its complex with trypsin have been crystallized. For I-2 two morphologically different crystal forms were obtained. Crystal form 1 is tetragonal, P4(1)22 or P4(3)22, with a = 55.45 (2), c = 129.1 (2) A and V = 3.97 (2) x 10(5) A(3). The crystals diffract X-rays very anisotropically, to less than 6 A resolution normal to the c* direction, but up to 3 A resolution in the other directions. Crystal form 2 is monoclinic, space group C2. The cell parameters show significant variation even for crystals in the same batch. The median parameters are: a = 83.9, b = 41.5, c = 45.7 A, beta = 95.9 degrees and V = 1.58 x 10(5) A(3). The diffraction pattern is isotropic and reflections up to 2.2 A resolution were observed. The crystals of the complex between bovine trypsin and I-2 (2:1) belong to the orthorhombic space group P2(1)2(1)2(1) with a = 73.49 (2), b = 120.56 (3), c = 70.04 (2) A and V = 6.206 (5) x 10(5) A(3). The crystals diffract up to 2.3 A resolution, and contain one complex of 60 100 Da in an asymmetric unit.
从小麦胚芽中分离得到一种鲍曼-伯克型胰蛋白酶抑制剂I-2，相对分子质量为14000，含123个氨基酸残基，并且已将其与胰蛋白酶的复合物进行了结晶。对于I-2，获得了两种形态不同的晶体形式。晶体形式1为四方晶系，空间群为P4(1)22或P4(3)22，a = 55.45(2)，c = 129.1(2) Å，V = 3.97(2)×10⁵ ų。这些晶体对X射线的衍射非常各向异性，在垂直于c*方向上分辨率小于6 Å，但在其他方向上可达3 Å分辨率。晶体形式2为单斜晶系，空间群为C2。即使对于同一批次的晶体，晶胞参数也显示出显著变化。中位参数为：a = 83.9，b = 41.5，c = 45.7 Å，β = 95.9°，V = 1.58×10⁵ ų。衍射图谱是各向同性的，观察到了高达2.2 Å分辨率的反射。牛胰蛋白酶与I-2(2:1)的复合物晶体属于正交空间群P2(1)2(1)2(1)，a = 73.49(2)，b = 120.56(3)，c = 70.04(2) Å，V = 6.206(5)×10⁵ ų。这些晶体衍射分辨率高达2.3 Å，并且在一个不对称单元中包含一个60 100 Da的复合物。
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