大肠杆菌胞嘧碱通透酶CodB结构和功能的研究

项目名称： 大肠杆菌胞嘧碱通透酶CodB结构和功能的研究

项目编号： No.31300618

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 生物科学

项目作者： 李硕

作者单位： 四川大学

项目金额： 22万元

中文摘要： 核糖碱基/阳离子同向转运蛋白-1（NCS1）家族涵盖了来自革兰氏阴性菌、革兰氏阳性菌、古生菌、酵母、真菌、植物等超过1000个蛋白成员。其中来自细菌和真菌的成员之间存在着明显的差异，在进化树上不能得到严密的聚类。NCS1家族蛋白在不同种类的生物中都负责摄取外源性核酸碱基。除此之外，该家族蛋白还在某些生物体内履行着转运代谢废物排出细胞的职责。尽管这类家族蛋白的生物学意义如此重要，除Mhp1以外，尚无任何一个细菌、真菌或者哺乳动物的NCS1家族蛋白的三维晶体结构被解析出来，对其功能特征的描述更是无从谈起。我们选择大肠杆菌胞嘧啶通透酶CodB为主要研究对象，希望通过对其三维晶体结构进行解析来了解NCS1家族蛋白转运底物进入细胞的分子机理，并且希望通过与已知结构的NCS2家族蛋白进行比较来探讨此类同向转运蛋白转运底物的结构特征和分子共性，借此加深对同向转运蛋白的了解和认识。

中文关键词： 膜蛋白；糖转运；SWEET转运蛋白；；

英文摘要： The Nucleobase/Cation Symporter-1 (NCS1) Family consists of over 1000 currently sequenced proteins, including Gram-negative and Gram-positive bacteria, archaea, yeast, fungi and plants. Among the proteins identified, the bacterial and yeast proteins could not cluster closely on the NCS1 family phylogenetic tree with divergent differentiation .The nucleobase/cation symporter-2 proteins，are responsible for the uptake of nucleobases in all kingdoms of life. Apart from thatNCS1 proteins play vital roles in elimination of metabolic waste products in certain species. Despite their increasing biological importance, studying NCS1 family members has been an on-going challenge due to the vast lack of knowledge in three-dimensional structure and functional characterization of the NCS1. Besides Mhp1, to decipher the other proteins' detailed structural and to elucidate their molecular information remain outstanding task.Here we choose the Escherichia coli cytosine permease CodB as main research object. It is important for the study of its three-dimensional crystal structure to enable comprehensive understanding of the molecular mechanism of NCS1 family protein transporter substrates into cells.Moreover, through detailed comparison to the known structure of NCS2 family proteins, we tend to explore common structural features

英文关键词： membrane proteins；sugar transportation；SWEET transporter；；