摘要
经过对蛋白质MAS的氨基酸序列进行分析、比对发现,其羧基末端含有一段高度保守的PDZ结合模序.据此推测,MAS通过此模序可能会与某些PDZ蛋白质发生相互作用.将MAS羧基末端27个氨基酸所对应的DNA序列,克隆到原核表达载体pGEX-4T-1中,构建重组质粒pGEX-MAS-CT.将重组质粒转入大肠杆菌BL21内,经IPTG诱导,并用glutathione-Sepharose 4B纯化,得到纯化的融合蛋白GST-MAS-CT.以GST-MAS-CT为饵蛋白,利用GST pull down方法,在兔脑组织中筛选与MAS特异结合的蛋白质.结果表明,在兔脑组织中有多种蛋白质可以与MAS-CT特异结合,经Western印迹检验其中之一为突触后致密物质-95(postsynaptic density protein95,PSD-95).PSD-95与MAS的相互作用的研究结果,为研究完整的MAS与PSD-95的相互作用以及这种相互作用对MAS受体的功能的影响奠定了基础.
The carboxyl terminal amino acid sequences of MAS protein is E-T-V-V, which conform to the consensus motif （E-S/T-X-I/L/V） for association with PDZ proteins. It was speculated that MAS may associate with some PDZ proteins via its carboxyl terminal to regulate MAS signaling. In this study pGEX-MAS-CT was first constructed by inserting the DNA fragment of MAS encoding the last 27 amino acids of its carboxyl terminal into the prokaryotic expression vector pGEX-4T-1. The recombinant construct pGEX-MAS-CT was successfully cloned and identified by EcoR Ⅰ and Xho Ⅰdigestion, PCR amplification and sequencing. GST-MAS-CT fusion protein was then robustly induced by ITPG and purified with glutathione-Sepharose 4B beads from the lysate of E. coli B[21, which was transformed in pGEX-MAS-CT. Rabbit brain lysates were pull-downed with GST-MAS-CT fusion protein conjugated with Glutathione-Sepharose 4B beads to screen novel binding proteins of MAS. Many proteins were able to be detected in the GST-MAS-CT pull-down complex but not in GST pull-down complex, with one of the binding proteins been identified as postsynaptic density protein 95（PSD-95） by Westem blot. These results provide a strong evidence for further studying the intro cellular association of the MAS and PSD-95 and also their potential physiological significances.
出处
《中国生物化学与分子生物学报》
CAS
CSCD
北大核心
2007年第5期370-374,共5页
Chinese Journal of Biochemistry and Molecular Biology
基金
国家自然科学基金项目(No.30371643
No.30572183)
北京市教委科技发展基金(No.KZ200610025013)
北京市优秀人才择优资助项目资助~~
