CALMODULIN STRUCTURE REFINED AT 1.7 ANGSTROM RESOLUTION
CALMODULIN STRUCTURE REFINED AT 1.7 ANGSTROM RESOLUTION
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DOI：
10.1016/0022-2836(92)90324-d
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发表时间：
1992-12-20
影响因子：
5.6
通讯作者：
QUIOCHO, FA
中科院分区：
文献类型：
--
作者：
CHATTOPADHYAYA, R;MEADOR, WE;QUIOCHO, FA
我们已经确定和完善的晶体结构的重组钙调素在1.7倍分辨率。使用2.2 μ m已发表的天然牛脑结构作为起始模型，通过分子置换确定结构。在10.0 ~ 1.7 σ范围内使用14，469次反射，结构因子超过0.5σ，最终的晶体学R因子为0.216。键长和键角距离与理想值的均方根偏差分别为0.009 μ m和0.032 μ m。最终模型由1279个非氢原子组成，其中包括4个钙离子，1130个蛋白质原子，其中包括3个双构象的Asp 118侧链原子，139个水分子和1个乙醇分子。钙调素残基1 ~ 4和148的电子密度定义不明确，除了残基4的主链原子外，未包括在我们的模型中。我们晶体中的钙调素结构与Babu及其同事早期描述的2.2 π结构非常相似，均方根偏差为0.36 π。钙调素仍然是一个哑铃形分子，具有相似的裂片，并通过中央α-螺旋连接。每个叶包含三个α-螺旋和两个Ca 2+结合EF手环，在相邻EF手环和一个非EF手环之间有一个短的反平行β-折叠。在中心螺旋结构上存在一些差异，晶体堆积被广泛研究，并解释了三斜晶体沿z轴沿着容易生长的原因。在这里，我们描述了氢键在各种二级结构元素和水合钙调蛋白。
We have determined and refined the crystal structure of a recombinant calmodulin at 1.7 Å resolution. The structure was determined by molecular replacement, using the 2.2 Å published native bovine brain structure as the starting model. The final crystallographicR-factor, using 14,469 reflections in the 10.0 to 1.7 Å range with structure factors exceeding 0.5σ, is 0.216. Bond lengths and bond angle distances have root-mean-square deviations from ideal values of 0.009 Å and 0.032 Å, respectively. The final model consists of 1279 non-hydrogen atoms, including four calcium ions, 1130 protein atoms, including three Asp118 side-chain atoms in double conformation, 139 water molecules and one ethanol molecule. The electron densities for residues 1 to 4 and 148 of calmodulin are poorly defined, and not included in our model, except for main-chain atoms of residue 4.The calmodulin structure from our crystals is very similar to the earlier 2.2 Å structure described by Babu and coworkers with a root-mean-square deviation of 0.36 Å. Calmodulin remains a dumb-bell-shaped molecule, with similar lobes and connected by a central α-helix. Each lobe contains three α-helices and two Ca2+binding EF hand loops, with a short antiparallel β-sheet between adjacent EF hand loops and one non-EF hand loop. There are some differences in the structure of the central helix.The crystal packing is extensively studied, and facile crystal growth along thez-axis of the triclinic crystals is explained. Herein, we describe hydrogen bonding in the various secondary structure elements and hydration of calmodulin.