Preliminary analysis of amphibian red cell M ferritin in a novel tetragonal unit cell
Preliminary analysis of amphibian red cell M ferritin in a novel tetragonal unit cell
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DOI：
10.1107/s0907444997003983
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发表时间：
1997-09-01
影响因子：
2.2
通讯作者：
Allewell, NM
中科院分区：
文献类型：
--
作者：
Ha, Y;Theil, EC;Allewell, NM
铁蛋白是一个多基因家族的蛋白质，在所有的原核和真核细胞中浓缩和储存铁。24个折叠成四螺旋束的单体亚基组装形成具有432立方对称性和类似于130埃的外径的蛋白质壳。铁被储存在蛋白质壳内，作为直径类似于80埃的矿化核心。重组两栖动物红细胞M铁蛋白在PH 4.6下类似于2M（NH4）（2）SO4结晶，空间群以前没有报道。使用电子显微镜、旋进摄影、天然蛋白质和UO 22+衍生物的帕特森和傅立叶图以及模拟来确定晶胞尺寸为a = B = 169.6，c = 481.2埃，α = β = γ = 90度，空间群为P4（1）2（1）2或P4（3）2（1）2。以两栖类红细胞L铁蛋白为模型，通过分子置换得到了其结构的初步模型。与先前确定的在两重和三重分子轴处具有分子间接触的铁蛋白晶体结构相反，M铁蛋白晶体具有由在四重分子轴处的两个分子的DE环的叉指型介导的新型分子间相互作用。
The ferritins are a multigene family of proteins that concentrate and store iron in all prokaryotic and eukaryotic cells. 24 monomeric subunits which fold as four-helix bundles assemble to form a protein shell with 432 cubic symmetry and an external diameter of similar to 130 Angstrom. The iron is stored inside the protein shell as a mineralized core similar to 80 Angstrom in diameter. Recombinant amphibian red cell M ferritin crystallizes in similar to 2M (NH4)(2)SO4 at PH 4.6 in a space group that has not been reported previously. Electron microscopy, precession photography, Patterson and Fourier maps of the native protein and a UO22+ derivative, and simulations were used to determine that the unit-cell dimensions are a = b = 169.6, c = 481.2 Angstrom, alpha = beta = gamma = 90 degrees and the space group is P4(1)2(1)2 or P4(3)2(1)2. A preliminary model of the structure was obtained by molecular replacement, with amphibian red cell L ferritin as the model. In contrast to previously determined ferritin crystal structures which have intermolecular contacts at the twofold and threefold molecular axes, M ferritin crystals have a novel intermolecular interaction mediated by interdigitation of the DE loops of two molecules at the fourfold molecular axes.