Molecular mechanisms of microheterogeneity‐induced defect formation in ferritin crystallization
Molecular mechanisms of microheterogeneity‐induced defect formation in ferritin crystallization
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铁蛋白结晶中微异质性诱导缺陷形成的分子机制
DOI：
10.1002/prot.1047
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
P. Vekilov
中科院分区：
文献类型：
--
作者：
S. Yau;B. R. Thomas;O. Galkin;O. Gliko;P. Vekilov
我们应用原子力显微镜原位结晶铁蛋白从含有105%（w/w）的固有分子二聚体的解决方案。分子分辨率成像显示，二聚体由两个结合的单体组成。组成单体可能部分变性，导致二聚体表面的疏水性增加。相应地，二聚体强烈地吸附在晶体表面上。吸附的二聚体阻碍了逐步生长，并在随后的晶体层中通过晶体引发多达10个三重和单空位的堆叠。空位周围的分子从它们的晶体学位置移动了0.1分子尺寸。位移使晶格应变，因此，在晶体尺寸> 200 μm时，累积的应变通过塑性变形而分解，于是晶体断裂成尺寸为20-50 μm的镶嵌块。铁蛋白和脱铁蛋白的镶嵌性的发病的临界大小是相似的，接近第三种蛋白质，溶菌酶的值，它也同意与理论预测。被困在铁蛋白和脱铁蛋白中的微晶诱导应变，其特征长度尺度等于单点缺陷的长度尺度，因此，捕获并不有助于镶嵌性。不希望的现象，包括异质性的产生，吸附，掺入，和由此产生的晶格应变和镶嵌在这个和其他蛋白质系统的序列，可以避免通过改进的方法来分离类似的蛋白质物种（微观异质性）或通过增加的生物化学稳定性的大分子对寡聚化。蛋白质2001;43：343-352.© 2001 Wiley利斯公司
We apply in situ atomic force microscopy to the crystallization of ferritins from solutions containing ≈5% (w/w) of their inherent molecular dimers. Molecular resolution imaging shows that the dimers consist of two bound monomers. The constituent monomers are likely partially denatured, resulting in increased hydrophobicity of the dimer surface. Correspondingly, the dimers strongly adsorb on the crystal surface. The adsorbed dimers hinder step growth and on incorporation by the crystal initiate stacks of up to 10 triple and single vacancies in the subsequent crystal layers. The molecules around the vacancies are shifted by ≈0.1 molecular dimensions from their crystallographic positions. The shifts strain the lattice and, as a consequence, at crystal sizes > 200 μm, the accumulated strain is resolved by a plastic deformation whereupon the crystal breaks into mosaic blocks 20–50 μm in size. The critical size for the onset of mosaicity is similar for ferritin and apoferritin and close to the value for a third protein, lysozyme; it also agrees with theoretical predictions. Trapped microcrystals in ferritin and apoferritin induce strain with a characteristic length scale equal to that of a single point defect, and, as a consequence, trapping does not contribute to the mosaicity. The sequence of undesired phenomena that include heterogeneity generation, adsorption, incorporation, and the resulting lattice strain and mosaicity in this and other proteins systems, could be avoided by improved methods to separate similar proteins species (microheterogeneity) or by increasing the biochemical stability of the macromolecules against oligomerization. Proteins 2001;43:343–352. © 2001 Wiley‐Liss, Inc.
影响因子：
5.6
作者：
S. Yau;D. Petsev;B. R. Thomas;P. Vekilov
通讯作者：
S. Yau;D. Petsev;B. R. Thomas;P. Vekilov
影响因子：
3.4
作者：
Petsev, DN;Thomas, BR;Vekilov, PG
通讯作者：
Vekilov, PG