Kawajiri K, Gotoh O, Sogawa K, Tagashira Y, Muramatsu M, Fujii-Kuriyama Y
Proc Natl Acad Sci U S A. 1984 Mar;81(6):1649-53. doi: 10.1073/pnas.81.6.1649.
We determined the coding nucleotide sequence of the mRNA for a 3-methylcholanthrene-inducible cytochrome P-450, P-450d, of rat liver by sequence analysis of cloned cDNAs. The predicted amino acid sequence of the cytochrome is composed of 513 amino acids, and its NH2-terminal sequence of 30 amino acids completely coincides with that reported from analysis of the purified cytochrome P-450d. The amino acid composition of the deduced sequence also agrees well with that determined from the purified protein. Computer-aided analysis was carried out to compare the complete primary structures of five species of cytochrome P-450, two molecular species of phenobarbital-inducible rat liver cytochrome P-450 (P-450b and P-450e), phenobarbital-inducible rabbit liver cytochrome P-450LM2, 3-methylcholanthrene-inducible rat liver cytochrome P-450d, and camphor-hydroxylating P-450 of Pseudomonas putida (P-450CAM). It is concluded therefrom that the time of divergence between cytochrome P-450b (P-450e) and P-450d is much earlier than that of branching between phenobarbital-inducible cytochromes P-450 of rat and rabbit. One highly conserved cysteine-containing region that is close to the COOH terminus is found in all of these cytochrome P-450 sequences, indicating that the heme-binding site is the cysteine residue in this region.
我们通过对克隆的cDNA进行序列分析，确定了大鼠肝脏中一种3-甲基胆蒽诱导型细胞色素P-450，即P-450d的mRNA编码核苷酸序列。该细胞色素的预测氨基酸序列由513个氨基酸组成，其30个氨基酸的NH2末端序列与从纯化的细胞色素P-450d分析中报道的序列完全一致。推导序列的氨基酸组成也与从纯化蛋白中确定的组成非常吻合。我们进行了计算机辅助分析，以比较五种细胞色素P-450的完整一级结构，这五种细胞色素分别是：两种苯巴比妥诱导型大鼠肝脏细胞色素P-450（P-450b和P-450e）、苯巴比妥诱导型兔肝脏细胞色素P-450LM2、3-甲基胆蒽诱导型大鼠肝脏细胞色素P-450d以及恶臭假单胞菌的樟脑羟化细胞色素P-450（P-450CAM）。由此得出结论，细胞色素P-450b（P-450e）和P-450d之间的分化时间比大鼠和兔的苯巴比妥诱导型细胞色素P-450之间的分支时间要早得多。在所有这些细胞色素P-450序列中都发现了一个靠近COOH末端的高度保守的含半胱氨酸区域，这表明血红素结合位点是该区域中的半胱氨酸残基。
