STRUCTURE OF PURPLE MEMBRANE FROM HALOBACTERIUM-HALOBIUM - ANALYSIS OF X-RAY-DIFFRACTION PATTERN
STRUCTURE OF PURPLE MEMBRANE FROM HALOBACTERIUM-HALOBIUM - ANALYSIS OF X-RAY-DIFFRACTION PATTERN
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DOI：
10.1016/0022-2836(75)90123-0
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发表时间：
1975-01-01
影响因子：
5.6
通讯作者：
HENDERSON, R
中科院分区：
文献类型：
--
作者：
HENDERSON, R
对盐杆菌紫膜定向标本的X射线衍射分析表明，蛋白质和脂质成分以aP 3六方晶格排列，每个不对称单元有一个蛋白质分子。该结构由单层蛋白质分子组成，在跨膜方向上矢量取向相同。赤道中心位于10 °，轴向位于5 °和1.5 °的强衍射峰的存在表明，构成膜大部分质量的蛋白质分子在相当大的程度上由α-螺旋组成，长度为25至35 °，膜的表面是平的，没有大到足以在悬浮介质的电子密度改变时影响X射线图案的凸起或凹坑。磷脂在晶格中的位置可能不如蛋白质精确，因为乙酸铀酰的存在（预期与酸性磷酸基团配位）仅在低分辨率下产生强度变化。
An X-ray diffraction analysis of oriented specimens of the purple membrane fromHalobacterium halobiumshows that the protein and lipid components are packed in aP3 hexagonal lattice, with one protein molecule per asymmetric unit. The structure is made up of a single layer of the protein molecules, oriented vectorially in the same direction across the membrane.The presence of strong diffraction peaks equatorially centred at 10 Å, and axially at 5 Å and 1.5 Å, show that the protein molecules, which make up most of the mass of the membrane, are composed to a considerable extent of α-helices, 25 to 35 Å long, arranged roughly perpendicular to the plane of the membrane to form superhelical groupings of the “coiled-coil” type.The surface of the membrane is flat, with no bumps or dimples large enough to affect the X-ray pattern when the electron density of the suspending medium is altered. The phospholipids may be less exactly positioned in the lattice than the protein, since the presence of uranyl acetate, which is expected to co-ordinate with the acidic phosphate groups, produces intensity changes only at low resolution.