香蕉(Musa acuminata)MaGBSSⅠ-3蛋白的亚细胞定位及其在毕赤酵母中的表达

Subcellular Localization and Pichia pastoris Expression of MaGBSS Ⅰ-3 from Banana(Musa acuminata)

颗粒结合型淀粉合成酶Ⅰ(granule-bound starch synthaseⅠ,GBSSⅠ)是决定果实直链淀粉合成的关键酶。研究GBSSⅠ的亚细胞定位及其在毕赤酵母中的表达,将为其蛋白功能验证奠定基础。本研究从巴西蕉(Musa acuminata L.AAA group cv.Brazilian)果实中克隆到一个GBSSⅠ成员,命名为Ma GBSSⅠ-3。生物信息学分析表明,Ma GBSSⅠ-3开放阅读框为675 bp,编码224个氨基酸,蛋白分子量为55.12 k D,等电点为5.38。聚类分析发现Ma GBSSⅠ-3与油棕Eg GBBSⅠ的亲缘关系较近。亚细胞定位显示,Ma GBSSⅠ-3定位于细胞膜。酵母表达系统分析发现,Ma GBSSⅠ-3蛋白的大小约为55.0 k D,与预测的分子量大小相一致,说明已成功获得了Ma GBSSⅠ-3表达蛋白,为进一步验证Ma GBSSⅠ-3蛋白的功能奠定了基础。

Granule-bound starch synthaseⅠ（GBSSⅠ） is responsible for amylose synthesis. Study on the subcellular localization and Pichia pastoris expression of GBSSⅠ will lay the foundation for the functional verification.The Ma GBSSⅠ-3 gene was cloned from banana（Musa acuminata） pulps by homologous cloning method. Sequence analysis revealed that the open reading frame of Ma GBSSⅠ-3 was 675 bp and encoded a protein including224 amino acids. Its relative molecular mass was approximately 55.12 k D, isoelectric point was 5.38. Phylogenetic tree analysis showed that Ma GBSSⅠ-3 has closest genetic relationship with Elaeis guineensis（Eg GBSSⅠ）.Ma GBSSⅠ-3 protein was localized in the cell membrane. The size of Ma GBSSⅠ-3 protein is 55.0 k D by yeast expression system analysis, which is consistent with a predicted molecular mass, confirming that it has successfully obtained the Ma GBSS Ⅰ-3 protein. The result laid the foundation for the subsequent functional verification of Ma GBSSⅠ-3 protein.