六品系猪SLA-2多肽结合区分子结构差异研究

为研究我国饲养的不同品系猪sLA_2抗原多肽结合区分子结构差异，设计引物，克隆了六品系猪SLA-2基因cDNA全长序列，用分子生物学软件分析其基因特征，比较各品系猪SLA-2分子结构差异，并通过同源模建显示变异住点的空间位置．结果表明，六品系猪SLA-2cDNA全长为1119bp，其中3-1097为编码区，共编码364个氨基酸，分别在第125，188，227，283位置出现半胱氨酸残基，含有2对链内二硫键．六品系猪SLA-2胞外区氨基酸差异主要集中在α1区的62-70及77-82和口2区的143-156．同源模建显示，这些变异位点均位于SLA-2多肽结合区的口螺旋结构上，推测可能与动物的抗病毒免疫特性有关．可为猪品系的改良及抗病毒免疫研究提供参考．

Analyzing the Difference of Peptide-binding Domain in SLA-2 from Six Breeds of Pigs

In order to study the molecular structure difference in peptide-binding domain(PBD)of SLA-2 from the main breeds of pigs raised in China,a pair of primers were designed to amplify the whole cDNA of SLA-2 from six breeds of pigs and then the genetic characteristics of the interest genes were analyzed by computer.The molecular structure difference in PBD of SLA-2 from six breeds of pigs were further analyzed followed by homology modeling to display the key variable amino acids.After cloning,sequencing and analyzing by computer,all SLA-2 alleles were 1 119bp and the 3-1 097 sites were the ORF domain which coded for 364 amino acids with two sets of disulfide bond in intro-chain constituted by four cysteines situated in 125,188,227 and 283 sites.The main variable amino acids of extra-cellular domain of SLA-2 in six breeds of pigs focused on 62-70 sites and 77-82 sites in α1 domain,and 143-156 sites in α2 domain.Homology modeling displayed that all variable amino acids located on the α-Helix strains PBD of SLA-2 molecule,which indicated that they might be associated with the anti-virus immune activity for these breeds of pigs.The study will supply significant data for improving the anti-virus capacity for the cultivated breed of swine.