Sequence homology and structural similarity between cytochrome b of mitochondrial complex III and the chloroplast b6-f complex: position of the cytochrome b hemes in the membrane.
Sequence homology and structural similarity between cytochrome b of mitochondrial complex III and the chloroplast b6-f complex: position of the cytochrome b hemes in the membrane.
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线粒体复合物 III 的细胞色素 b 与叶绿体 b6-f 复合物之间的序列同源性和结构相似性：细胞色素 b 血红素在膜中的位置。
DOI：
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发表时间：
1984
影响因子：
11.1
通讯作者：
A. Trebst
中科院分区：
文献类型：
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作者：
W. Widger;W. Cramer;R. Herrmann;A. Trebst
来自五种不同线粒体来源(人、牛、小鼠、酵母和尼杜拉曲霉)的复合体III的细胞色素b的氨基酸序列与菠菜的叶绿体细胞色素b6具有高度的同源性。对具有“疏水”功能的疏水残基分布的计算表明，42kDa线粒体细胞色素的膜折叠模式涉及8-9个跨膜结构域。较小的23 kDa叶绿体细胞色素似乎在五个跨域中折叠，这些跨域与线粒体的前五个类似。四个高度保守的组氨酸被认为是这两个亚铁血红素的可能配体。组氨酸沿跨膜段和跨膜α螺旋的横截面上的位置表明，两个配基对His-82-His-197/198和His-96-His-183桥接跨膜肽II和V，并且两个血红素位于疏水膜核心的相反侧。此外，叶绿体b6-f复合体的17-kDa蛋白似乎包含线粒体细胞色素b多肽的COOH末端的一个或多个功能。
The amino acid sequences of cytochrome b of complex III from five different mitochondrial sources (human, bovine, mouse, yeast, and Aspergillus nidulans) and the chloroplast cytochrome b6 from spinach show a high degree of homology. Calculation of the distribution of hydrophobic residues with a "hydropathy" function that is conserved in this family of proteins implies that the membrane-folding pattern of the 42-kilodalton (kDa) mitochondrial cytochromes involves 8-9 membrane-spanning domains. The smaller 23-kDa chloroplast cytochrome appears to fold in five spanning domains that are similar to the first five of the mitochondria. Four highly conserved histidines are considered to be the likely ligands for the two hemes. The positions of the histidines along the spanning segments and in a cross section of the membrane-spanning alpha helices implies that two ligand pairs, His-82-His-197/198 and His-96-His-183, bridge the spanning peptides II and V, and the two hemes reside on opposite sides of the hydrophobic membrane core. In addition, the 17-kDa protein of the chloroplast b6-f complex appears to contain one or more of the functions of the COOH-terminal end of the mitochondrial cytochrome b polypeptide.