分子遗传和蛋白质化学特性的细胞色素ba3栖热菌属酸奶HB8。
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Keightley是的,齐默尔曼BH、马瑟MW Springer P, Pastuszyn,劳伦斯DM,费用是
分子遗传和蛋白质化学特性的细胞色素ba3栖热菌属酸奶HB8。
J生物化学杂志。1995年9月1;270 (35):20345 - 58。
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7657607 (在PubMed]
- 文摘
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栖热菌属酸奶HB8细胞生长在分子氧减少紧张含有血红素的大幅增加,其中大部分似乎是由于末端氧化酶的存在,细胞色素ba3。我们描述一个净化过程,这种酶产量大约100毫克的纯蛋白质从2公斤的湿质量的细胞生长在< = 50 microM O2。检查SDS-polyacrylamide蛋白质的凝胶电泳后通过与Coomassie蓝染色显示一个强烈染色乐队大约在35 kDa,一个非常弱的染色乐队大约在18 kDa(齐默尔曼、林丙辉早些时候报道、Nitsche、C.I.费,j . A。Rusnak F。,Munck大肠(1988)Proc。国家的。学会科学。美国85年,5779 - 5783)。相比之下,治疗与硝酸银的凝胶显示更大的多肽污渍很弱,而较小的多肽污渍非常强烈。这些结果表明两个多肽在这种蛋白质的存在。使用部分氨基酸序列来自蛋白质获得DNA序列信息,我们孤立和测序栖热菌属的一部分包含更大的蛋白质编码的基因的染色体,亚基我(cbaA)和较小的蛋白质亚基二世(cbaB)。这两个多肽使用反相液相色谱分离,和他们的摩尔百分数氨基酸成分符合该翻译各自的基因。 The two genes appear to be part of a larger operon, but we have not extended the sequencing to identify initiation and termination sequences. The deduced amino acid sequence of subunit I includes the six canonical histidine residues involved in binding the low spin heme B and the binuclear center Cu(B)/heme A. These and other conserved amino acids are placed along the polypeptide among alternating hydrophobic and hydrophilic segments in a pattern that shows clear homology to other members of the heme- and copper-requiring terminal oxidases. The deduced amino acid sequence of the subunit II contains the CuA binding motif, including two cysteines, two histidines, and a methionine, but, in contrast to most other subunits II, it has only one region of hydrophobic sequence near its N terminus. Alignment of these two polypeptides with other cytochrome c and quinol oxidases, combined with secondary structure analysis and previous spectral studies, clearly establish cytochrome ba3 as a bona fide member of the superfamily of heme- and copper-requiring oxidases. The alignments further indicate that cytochrome ba3 is phylogenetically distant from other cytochrome c and quinol oxidases, and they substantially decrease the number of conserved amino acid residues.