Abstract: Natural resistance associated macrophage protein (NRAMP) is a major class of membrane transporters widely found in animals, plants and microorganisms, and play an important role in transporting and reusing heavy metal ions in plants. For exploring the biological characteristics of NRAMP gene family in Andrographis paniculata, seven NRAMP gene family members were screened and identified from the whole genome, named ApNRAMP1–ApNRAMP7, and their gene structures and physicochemical properties of the encoded proteins were analyzed. The results showed that the proteins encoded by ApNRAMPs genes ranged from 513 aa to 553 aa in length, and their molecular weight were between 56.00 kD and 60.54 kD. The subcellular localizations of all members were in the cell membrane. Phylogenetic analysis found that the NRAMP gene family was divided into two subfamilies. ApNRAMP3–ApNRAMP6 in Group Ⅰ contained 3 introns, while ApNRAMP1, ApNRAMP2, and ApNRAMP7 in Group Ⅱ contained 12 introns, and their encoded protein sequences all contained Motif1–8 sequences. Protein structure prediction analysis showed that the secondary structures of ApNRAMPs proteins were mainly composed of α-helix and random coil, and the three-dimensional structures were relatively similar. This study provides a reference for further elucidation of the molecular mechanism of ApNRAMPs genes involvement in cadmium stress response.

摘要： 自然抗性相关巨噬细胞蛋白(Natural resistance associated macrophage protein，NRAMP)是一类广泛存在于动植物及微生物中重要的膜转运蛋白，在植物重金属离子转运和重新利用中起着重要作用。为探究穿心莲Andrographis paniculata的NRAMP基因家族生物学特性，本研究根据拟南芥NRAMP家族的蛋白序列，从穿心莲全基因组中筛选鉴定了7个NRAMP家族成员，命名为ApNRAMP1～ApNRAMP7，并分析其基因结构和编码蛋白的理化性质等相关信息。结果表明，ApNRAMPs基因编码蛋白的长度为513～553 aa，分子量在56.00～60.54 kD之间，所有成员均定位于细胞膜上。系统进化分析表明，NRAMP基因家族分为2个亚家族。基因结构分析发现，属于GroupⅡ的ApNRAMP3～ApNRAMP6含有3个内含子，而属于GroupⅠ的ApNRAMP1、ApNRAMP2、ApNRAMP7则含有12个内含子；保守基序分析发现，Motif1～8保守基序存在于所有的ApNRAMPs编码的蛋白序列。蛋白结构预测分析发现，ApNRAMPs蛋白二级结构主要由α-螺旋和无规则卷曲构成，三维结构较为相似。该研究结果为进一步解析ApNRAMPs基因参与镉胁迫响应的分子机制提供参考。