一种节节麦高分子量麦谷蛋白与小麦同源蛋白氨基酸序列的比较

A Novel High Molecular Weight Glutenin Subunit from Aegilops tauschii and Its' Deduced Amino Acid Sequences Comparison with Those of Homologous from Common Wheat

对节节麦的一种y类高分子量麦谷蛋白基因进行了序列测定和比较。结果显示,该亚基与小麦A、B和D和节节麦D染色体编码的y型亚基的全蛋白氨基酸残基数目均不一致。6个y型基因的信号肽、N-端和C-端氨基酸残基数目均一致,但有个别氨基酸的替换。而重复区氨基酸残基数目均不一致,主要由于重复单元六肽和九肽的数目不等。在目前已知的D基因组编码的y型亚基中,Dy13t的重复区是最短的,它比Dy10少4个九肽,比Dy12少4个九肽,2个六肽,比Dy12t少4个九肽。由N-Calign序列所作的聚类分析将这6个y型亚基分为3支,A、B和D基因组编码的亚基各占一支。来源于D基因组的4个基因的一支,又可将来源于节节麦和小麦D基因组的2个基因分别聚类在一起。

A novel ytype high molecular glutenin gene, Dy13t, was cloned and sequenced from Aegilops tauschii. The deduced amino acid sequence of Dy13t was compared with those of homologous of common wheat and Aegilops tauschii. The result indicates that the whole protein amino acid sequence of Dy13t, is different from those of genes encoded either by common wheat A, B and D genome or by Aegilops tauschii D genome which we have known. The comparison results also show that the amino acid residues of signal peptide, Nterminal and Cterminal of six genes are the same except for a few amino acid residues substitution. The divergence of 6 genes is made by the difference of repetitive domain, especially by the variation of repeated hexpeptide (PGQGQQ) and nonapeptide (GYYPTSP/SQQ or GY/HYPT/ASLQQ). Up till now, the repetitive domain of Dy13t is the shortest in the D genome encoded genes. When the repetitive domain of Dy13t is compared with Dy10, Dy12 and Dy12t, 4 nonapeptide, 4 nonapeptide, 2 hexpeptide, and 4 nonapeptide lack Dy13t respectively. According to the NC aligned sequences cluster results, the 6 genes can be divided into 3 branches, each of the A, B and D genome encoded genes is included in the same branch. The 4 D genome encoded genes are clustered in the same branch, each of the 2 genes from common wheat D genome and Aegilops tauschii D genome are clustered in the same subbranch.