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细胞色素P450在各种内源和外源物质代谢中起着非常重要的作用。利用豌豆蚜Acyrthosiphon pisum基因组mRNA和氨基酸数据库研究P450基因功能的进化规律。通过生物信息学方法对豌豆蚜全基因组P450进行分析,结果显示:在豌豆蚜基因组中发现69个P450基因,它们分别属于13个P450家族和18个亚家族,是一个典型的多基因家族。进一步将这些基因与豌豆蚜ESTs数据库进行了比对分析,其中39个候选基因有EST证据,证明了这些P450基因在转录水平的真实性。以氨基酸相似度大于60%为标准对豌豆蚜基因组中P450基因进行分组,69个P450基因中,除18个基因序列因差异太大,不能被归入任何一组,其余51个可归入10个组,其中8个组(包含47条序列)适合于正选择和基因转换分析。正选择和基因转换分析结果表明:仅有1个组(含9个基因)显著受到正选择压力作用,正选择概率大于95%的氨基酸位点分别是20T和27N,20T位于底物识别位点SRS1,27N位于D-helix;有3个组(包含8个基因)显示显著的基因转换事件。参与基因转换的基因均为CYP4家族成员,分别是CYP4C,CYP4G和CYP4V亚家族。参与基因转换的成员之间的蛋白相似度较高(70%～95%),且XM_001944991与XM_001951794同存在于SCAFFOLD12542上,XM_001945510与XM_001944057同存在于SCAFFOLD7010上。这可能暗示豌豆蚜P450基因通过基因复制,然后通过基因转换使P450获得新的功能,以适应多变的生存环境。此外,鉴定出20个不同的基序,其中有5条基序在90%以上的基因中出现。
Cytochrome P450 plays a very important role in the metabolism of various endogenous and exogenous substances. The evolution of P450 gene function was studied by using Acyrthosiphon pisum genomic mRNA and amino acid database. The genome-wide P450 of pea aphid was analyzed by bioinformatics method. The results showed that 69 P450 genes were found in the genome of pea aphid, they belong to 13 P450 families and 18 subfamilies, respectively, which is a typical multigene family. Further comparison of these genes with the ESTs database of pea aphids showed that 39 of the candidate genes had EST evidence that these P450 genes were authenticated at the transcriptional level. The P450 genes in the genome of pea aphid were grouped according to the amino acid similarity greater than 60%. Among the 69 P450 genes, except for 18 gene sequences, which could not be classified into any one group, the other 51 were classified as 10 Eight groups, of which eight (containing 47 sequences) are suitable for positive selection and gene transfer analysis. Positive selection and gene transfer analysis showed that only one group (including nine genes) was significantly under positive selection pressure. The amino acid sites with the positive selection probability greater than 95% were 20T and 27N respectively. The 20T was located at the substrate recognition site SRS1, 27N are located in D-helix; three groups (containing eight genes) show significant gene switching events. Genes involved in gene conversion are members of the CYP4 family, which are the CYP4C, CYP4G and CYP4V subfamilies, respectively. The protein similarity between the members involved in gene conversion is high (70% -95%), and XM_001944991 and XM_001951794 exist on SCAFFOLD12542, while XM_001945510 and XM_001944057 exist on SCAFFOLD7010. This may suggest that the P450 gene in the pea aphid passes the gene duplication, and then the P450 is given new functions through gene transformation to adapt to the changing living environment. In addition, 20 different motifs were identified, of which 5 motifs appeared in more than 90% of the genes.