MOLECULAR-CLONING AND NUCLEOTIDE-SEQUENCE OF CDNA FOR MESSENGER-RNA OF MITOCHONDRIAL CYTOCHROME-P-450(SCC) OF BOVINE ADRENAL-CORTEX
MOLECULAR-CLONING AND NUCLEOTIDE-SEQUENCE OF CDNA FOR MESSENGER-RNA OF MITOCHONDRIAL CYTOCHROME-P-450(SCC) OF BOVINE ADRENAL-CORTEX
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DOI：
10.1073/pnas.81.15.4647
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发表时间：
1984-01-01
期刊：
影响因子：
--
通讯作者：
OMURA, T
中科院分区：
文献类型：
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作者：
MOROHASHI, K;FUJIIKURIYAMA, Y;OMURA, T
使用合成的寡核苷酸作为探针，分离了细胞色素P-450（SCC）mRNA的cDNA [互补DNA]克隆，细胞色素P-450催化牛肾上腺皮质线粒体中胆固醇的侧链裂解反应。对克隆的cDNA进行序列分析，能够推导出P-450（SCC）的前体形式的一级结构，其由520个氨基酸组成，并在NH 2末端含有39个氨基酸的额外肽。预测结构中第40 - 55位氨基酸残基的氨基酸序列与纯化的P-450（SCC）的NH 2-末端部分的序列完全一致。从预测的结构计算的氨基酸组成显示出良好的协议与纯化的蛋白质确定。前体分子的外肽类似于迄今报道的一些核编码的酵母线粒体蛋白。虽然P-450（SCC）是线粒体的组成部分，但其一级结构与其他形式的细胞色素P-450的一级结构的比较表明，P-450（SCC）在结构上与微粒体细胞色素P-450的相关性大于与细菌细胞色素P-450 cam的相关性。与各种形式的细胞色素P-450观察到的同源序列在P-450（SCC）分子中也高度保守。在成熟形式的P-450（SCC）中仅存在2个半胱氨酰残基，其中一个位于保守序列的中间，证实了该半胱氨酰残基作为血红素的第五配体的功能。
cDNA [complementary DNA] clones of the mRNA for cytochrome P-450(SCC), which catalyzes the side-chain cleavage reaction of cholesterol in bovine adrenal cortex mitochondria, were isolated by using synthetic oligonucleotides as probes. Sequence analysis of the cloned cDNA enabled the primary structure of the precursor form of P-450(SCC), which consisted of 520 amino acids and contained an extra peptide of 39 amino acids at the NH2 terminus, to be deduced. The amino acid sequence from the 40th to 55th amino acid residue in the predicted structure completely coincided with the sequence of the NH2-terminal portion of purified P-450(SCC). The amino acid composition calculated from the predicted structure showed an excellent agreement with that determined with the purified protein. The extrapeptide of the precursor molecule resembles those of a few nuclear-encoded yeast mitochondrial proteins reported so far. Although P-450(SCC) is a component of mitochondrial, comparison of its primary structure with those of other forms of cytochrome P-450 shows that P-450(SCC) is structurally more related to microsomal cytochrome P-450 than to a bacterial cytochrome P-450cam. A homologous sequence observed with various forms of cytochrome P-450 is also highly conserved in the P-450(SCC) molecule. Only 2 cysteinyl residues are present in the mature form of P-450(SCC), one of which is located in the middle of the conserved sequence, confirming the function of this cysteinyl residue as the fifth ligand of the heme.