A novel three-dimensional crystal of bacteriorhodopsin obtained by successive fusion of the vesicular assemblies.
A novel three-dimensional crystal of bacteriorhodopsin obtained by successive fusion of the vesicular assemblies.
复制标题
通过囊泡组件的连续融合获得的新型细菌视紫红质三维晶体。
DOI：
--
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发表时间：
1998
影响因子：
5.6
通讯作者：
T. Kouyama
中科院分区：
文献类型：
--
作者：
K. Takeda;Hidenori Sato;T. Hino;M. Kono;K. Fukuda;I. Sakurai;T. Okada;T. Kouyama
当细菌视紫红质（bR）的二维晶体（紫色膜）与少量中性去污剂辛硫葡萄糖苷在沉淀剂硫酸铵存在下在高温（32℃）下孵育时，大部分膜碎片转化为直径为50 nm的球形囊泡，当沉淀剂浓度升高时，这些囊泡能够组装成光学各向同性的六方晶体。增加了。紫色膜的囊泡化是在去垢剂与水相的混溶性变得非常低的条件下发生的，我们认为这是通过去垢剂分子插入膜中引发的。在低温下，向囊泡结构的转变受到抑制，并且膜/洗涤剂/沉淀剂混合物不会直接产生大晶体。然而，当将高温下产生的球形囊泡的悬浮液冷却并浓缩到15℃以下时，会产生双折射六方晶体，其衍射X射线的分辨率超过2.5A。这种新晶体属于P622空间群，晶胞尺寸为a=b=104.7 A和c=114.1 A，它由堆叠的平面膜组成，每个膜中bR三聚体排列在蜂窝晶格上，蛋白质之间的空间充满洗涤剂分子和天然脂质。这些堆叠膜被认为是通过球形囊泡的连续融合产生的。这意味着无需任何蛋白质完全溶解的步骤即可实现结晶。本结果提供了一种独特的结晶方法，可适用于在过量去污剂存在下容易变性的膜蛋白。
When the two-dimensional crystal of bacteriorhodopsin (bR), purple membrane, is incubated at high temperature (32 degreesC) with a small amount of the neutral detergent octylthioglucoside in the presence of the precipitant ammonium sulfate, a large fraction of the membrane fragments is converted into spherical vesicles with a diameter of 50 nm, which are able to assemble into optically isotropic hexagonal crystals when the precipitant concentration is increased. The vesicularization of purple membrane takes place under such a condition that the miscibility of the detergent to the aqueous phase becomes very low, and we suggest that it is initiated by insertion of the detergent molecules into the membrane. At low temperature, the transformation into the vesicular structure is inhibited and no large crystal is produced directly from membrane/detergent/precipitant mixtures. When a suspension of the spherical vesicles produced at the high temperature is cooled and concentrated below 15 degreesC, however, a birefringent hexagonal crystal is produced that diffracts X-rays beyond 2.5 A resolution. This new crystal belongs to the space group P622 with unit cell dimensions of a=b=104.7 A and c=114.1 A, and it is shown to be made up of stacked planar membranes, in each of which the bR trimers are arranged on a honeycomb lattice and the space among the proteins is filled with the detergent molecules and native lipids. These stacked membranes are suggested to be produced by successive fusion of the spherical vesicles. This implies that the crystallization is achieved without any step for complete solubilization of the protein. The present result offers a unique crystallization method that may be applicable to such membrane proteins that are liable to denature in the presence of an excess amount of detergent.
影响因子：
5.6
作者：
HENDERSON, R;BALDWIN, JM;DOWNING, KH
通讯作者：
DOWNING, KH
用盐杆菌脂质重建细菌视紫红质囊泡。
DOI：
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发表时间：
1982
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Höjeberg,B;Lind,C;Khorana,HG
通讯作者：
Khorana,HG