农杆菌双组分信号转导系统中VirG蛋白结构与转化功能的分析

农杆菌介导的转化方法在植物、真菌基因转化上有着重要意义,其中VirG蛋白起着重要作用.利用多种序列、结构分析对比软件,对根癌农杆菌和发根农杆菌4种代表性VirG蛋白基本性质、一级结构、二级结构、三级结构和表面静电势进行了预测比较和分析,发现N端差异较大.来自发根农杆菌的VirG蛋白更是在N端缺失了一段氨基酸,这可能是发根农杆菌转化效率低于根癌农杆菌的一个重要原因.结合文献关于定点突变的研究结果,经过总结分析VirG蛋白各位点突变对功能的影响,发现只有诸如N54和I77等少数位点的突变才对功能有促进作用.这些研究结果为提高农杆菌,尤其是发根农杆菌的侵染能力和范围提供了理论依据.

Analysis on the Structure and Function of VirG Proteins Belonging to Two-Component Signal Transduction System from Agrobacterium

Agrobacterium transformation system is an excellent transformation system. The basic characters, primary parameters,secondary and tertiary structures and surface electrostatic potential of four VirG proteins from Agrobacterium tumefaciens and Agrobacterium rhizogenes were compared with bioinformatics tools. Four VirG proteins have the high similarities of their sequences and structures except the N-terminal. The VirG4 protein which belongs to Agrobacterium rhizogenes lacks amino acid sequence of N-terminal, which should be the reason for the lower transformation efficiency than Agrobacterium tumefaciens. With the literature review,only several key residues,such as N54 and I77 are able to improve the function of VirG protein after mutation. The results are helpful for enhancing the abilities of Agrobacterium,especially for Agrobacterium rhizogenes.