植物镉富集PCS基因的生物信息学分析

Bioinformatics Analysis of the PCS Genes Related With Cadmium Enrichment in Plants

植物络合素是植物细胞中的小分子多肽,可以螯合重金属离子并储存于液泡中,起到降低毒性和富集重金属的作用。植物络合素合酶基因(PCS)是植物络合素合成过程的关键基因,本研究对15种植物镉(Cd2+)富集相关的PCS基因序列进行了生物信息学分析。结果表明,PCS具有保守的外显子组成;位于PCS肽链N端的氨基酸序列一致率达到82.54%,位于C端的氨基酸序列一致率为63.37%;PCS含量最多的氨基酸为亮氨酸(11.17%),色氨酸含量最少(1.63%);PCS具有保守的催化活性中心Cys70、His176、Asp194;不同PCS基因的密码子偏好使用性差异明显,高频密码子平均数量超过9个。研究结果显示,不同PCS基因既有保守的结构组成,也显现出种属的差异,可以用于物种的分类和亲缘关系分析。研究结果为PCS基因的功能及作用机制研究提供了重要的科学依据。

Phytochelatins are micromolecule peptides that can chelate heavy metal ions to reduce its toxicity to plants. The chelate compounds were further imported into the vacuoles and restored as compartmentation of heavy metal ions. Phytochelatin synthase （PCS） plays a crucial role in the synthesis of phytochelatins. The research here is to analyze the PCS genes related to cadmium enrichment from 15 kinds of plants. Sequence alignment showed their exon structure highly conserved. The identity rate of amino acid at N-terminal of the PCS peptides was 82.54% while 63.37% at C- terminal. The PCS peptide had the highest proportion of Leucine （11. 17% ） and lowest proportion of tryptophon （ 1.63% ）. The conserved catalytic active center of PCS was revealed as Cys^70, His^176 and Asp^194. The codon usage varied among different PCS genes with the average high-frequency codon number over 9. The results of the study clearly showed that the PCS genes have the conserved structure but also have the species characteristics, which could be used in classification and phylogenetic analysis of plants. It would be an important platform for the further study of gene function and mechanism in cadmium enrichment in future.