BOVINE SEMINAL RIBONUCLEASE - STRUCTURE AT 1.9-ANGSTROM RESOLUTION
BOVINE SEMINAL RIBONUCLEASE - STRUCTURE AT 1.9-ANGSTROM RESOLUTION
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DOI：
10.1107/s0907444993003403
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发表时间：
1993-07-01
期刊：
影响因子：
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通讯作者：
ZAGARI, A
中科院分区：
文献类型：
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作者：
MAZZARELLA, L;CAPASSO, S;ZAGARI, A
牛精液核糖核酸酶的晶体结构，同源二聚体酶密切相关的胰腺核糖核酸酶，已被细化在一个正常的分辨率为1.9埃，采用电子区域检测器上收集的数据。最终的模型由两条链组成，每个不对称单元包含1990个非H原子，7个硫酸根阴离子和113个水分子。晶胞参数为a = 36.5（1），B = 66.7（1），c = 107.5（2）埃，空间群为P22（1）2（1）。在6.0-1.9埃的分辨率范围内，对16492个反射，R因子为0.177，键长和键角与理想值的偏差分别为0.020埃和3.7度。该分子由两个胰样链形成，其N-末端片段互换，使得每个活性位点由来自两个亚基的残基形成。这两条链由非晶体学双重对称性相关，并由两个连续的二硫桥共价连接，形成一个不寻常的十六元环跨越二聚体界面。偏离分子对称性，水化壳和硫酸盐结合位点也讨论了与已知的结构的胰腺酶。
The crystal structure of bovine seminal ribonuclease, a homodimeric enzyme closely related to pancreatic ribonuclease, has been refined at a normal resolution of 1.9 angstrom employing data collected on an electronic area detector. The final model consists of two chains containing 1990 non-H atoms, seven sulfate anions and 113 water molecules per asymmetric unit. The unit-cell parameters are a = 36.5 (1), b = 66.7 (1) and c = 107.5 (2) angstrom, space group P22(1)2(1). The R factor is 0.177 for 16 492 reflections in the resolution range 6.0-1.9 angstrom and the deviations from ideal values of bond lengths and bond angles are 0.020 angstrom and 3.7-degrees, respectively. The molecule is formed by two pancreatic like chains, which have their N-terminal segments interchanged so that each active site is formed by residues from both subunits. The two chains are related by a non-crystallographic twofold symmetry and are covalently linked by two consecutive disulfide bridges, which form an unusual sixteen-membered ring across the dimer interface. The deviations from the molecular symmetry, the hydration shell and the sulfate-binding sites are also discussed in relation to the known structure of the pancreatic enzyme.