The orientation of cytochromes in membrane multilayers prepared from aerobically grown Escherichia coli K12.
The orientation of cytochromes in membrane multilayers prepared from aerobically grown Escherichia coli K12.
复制标题
由需氧生长的大肠杆菌 K12 制备的多层膜中细胞色素的方向。
DOI：
10.1099/00221287-119-1-145
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
Ohnishi,T
中科院分区：
文献类型：
--
作者：
Poole,RK;Blum,H;Scott,RI;Collinge,A;Ohnishi,T
将从超声破碎的大肠杆菌K12制备的膜小泡离心到平面上，然后缓慢、部分脱水，导致膜平面相对于彼此和支撑表面的高度平行取向。这种膜多层膜在电子顺磁共振(E.P.R.)的磁场中绕平行于膜平面的单轴旋转。分光计可以推断各向异性顺磁中心的取向。细胞色素E.P.R.角度依赖性的计算机模拟光谱显示两个或三个细胞色素相对于膜平面定向良好。低自旋的细胞色素位于膜平面内，其法线位于膜平面内。一个(或两个)高自旋细胞色素(S)与其膜平面成45°角。因此，低自旋细胞色素血红素的取向与高等动物、微生物细胞和细菌脱氮副球藻线粒体中发现的inb型细胞色素和戏剧型细胞色素氧化酶的取向相同。讨论了这种低自旋成分可能是末端氧化酶--细胞色素。
Centrifugation of membrane vesicles, prepared from ultrasonically disruptedEscherichia coliK12, on to a planar surface followed by slow, partial dehydration results in a high degree of parallel orientation of the membrane planes with respect to each other and the supporting surface. Rotation of such membrane multilayers about a single axis parallel with the membrane planes within the magnetic field of an electron paramagnetic resonance (e.p.r.) spectrometer allows the orientation of anisotropic paramagnetic centres to be deduced. Computer simulations of the angular dependence of cytochrome e.p.r. spectra show two, or perhaps three, cytochromes, well-oriented with respect to the membrane plane. A low-spin cytochrome is oriented with the normal to its haem plane lying in the membrane plane. One (or perhaps two) high-spin cytochrome(s) lies with its haem plane making an angle of 45° with the membrane plane. The orientation of the low-spin cytochrome haem is thus the same as that of haems inb-type cytochromes and cytochrome oxidases of theatype found in the mitochondria of higher animal and microbial cells and the bacteriumParacoccus denitrificans. The possible identity of this low-spin component as the terminal oxidase, cytochromeo, is discussed.