摘要
为获知甜高粱蔗糖转运蛋白基因SUT1及其功能,采用同源克隆方法结合RACE技术克隆甜高粱SUT1基因,并对其进行生物信息学分析。克隆得到甜高粱蔗糖转运蛋白基因SUT1 c DNA全长为2 472bp,包括1 560bp编码区序列,编码含有519个氨基酸的蛋白。该蛋白是1个疏水性膜蛋白,分子量约为55k Da,理论等电点p I为8.86;无信号肽剪切位点,含有12个明显的跨膜螺旋拓扑结构,预测含有6个丝氨酸激酶磷酸化位点、4个苏氨酸激酶磷酸化位点和2个酪氨酸激酶磷酸化位点;包含1段低复杂度序列和12个保守的跨膜螺旋结构域。在亚细胞水平,SUT1主要定位于叶绿体类囊体膜、质膜、高尔基体及内质网膜上;二级结构主要以α-螺旋为主,其中α-螺旋占43.35%,无规则卷曲占34.68%,延伸链占19.08%,β-转角占2.89%;预测SUT1蛋白主要在运载结合中发挥重要作用。SUT1基因表达分析结果表明,SUT1基因在各组织中均有表达,叶中表达量最高,其次分别为叶鞘、茎和根,穗中表达量最低。SUT1基因的克隆及其结构、性质与功能的初步分析,可为研究该基因在甜高粱源库互作关系中的功能机制奠定基础。
In this study,to learn the structure and function of the sucrose transporter gene（ SUT1） of sweet sorghum,we first obtained the full-length c DNA of SUT1 by using homology-based cloning together with RACE technology. The c DNA sequence was then analyzed by using a variety of bioinformatics databases and software. The full-length c DNA of SUT1 contained 2472 base pairs,with a coding region of 1560 base pairs. This sequence encoded a protein of 519 amino acids in length with a molecular weight of 55 k Da and a theoretical isoelectric point（ p I） of 8. 86. SUT1 was found to encode a hydrophobic membrane protein for which there was no signal peptide and corresponding cleavage site in its sequence.The SUT1 protein ’s topology featured 12 distinct transmembrane helices, 12 conserved domains, six serine phosphorylation sites,four threonine phosphorylation sites,two tyrosine phosphorylation sites,and a low complexity region. At the subcellular level,the SUT1 protein was mainly localized to the chloroplast thylakoid membrane,plasma membrane,Golgi body,and the membrane of endoplasmic reticulum. The secondary structure of SUT1 was mainly composed of alpha helix,consisting of 43. 35% helix,34. 68% random coil,19. 08% extended strand,and 2. 89% beta turn. The SUT1 protein seemed to mainly play a role in the processes of transport and binding. The analysis of SUT1 gene expression indicated that it was expressed at varying levels in different tissues. The highest expression levels were found in the leaves,followed by the sheath,stem,and root,respectively,with the lowest expression in the tassel. By cloning the SUT1 gene and preliminarily predicting its structure,nature and functions,we have acquired valuable information which can be used to study the biological function of the SUT1 gene with respect to the relationship between source and sink in sweet sorghum.
出处
《核农学报》
CAS
CSCD
北大核心
2015年第12期2276-2286,共11页
Journal of Nuclear Agricultural Sciences
基金
国家自然科学青年基金项目(31101194)
国家杂粮工程技术研究中心建设项目(2011FU125X07)
黑龙江农垦总局科技攻关项目
