PICK1中N端酸性区域对其PDZ结构域脂质结合能力的调节  

Regulation of Liposome Binding of PDZ Domain by Its Adjacent N-terminal Acidic Region

作　　者：杨廷[1] 贾原[2] 肖虹[3] 石亚伟[1] 

机构地区：[1]教育部化学生物学与分子工程重点实验室,山西大学生物技术研究所,太原030006 [2]山西医学科学院生物治疗科中心实验室,太原030006 [3]山西医科大学第一医院病理科,太原030001

出　　处：《中国生物化学与分子生物学报》2012年第10期940-945,共6页Chinese Journal of Biochemistry and Molecular Biology

基　　金：国家自然科学基金项目(No.30400065,No.31170748);山西省自然科学基金项目资助(No.2007021033)~~

摘　　要：蛋白激酶Cα相互作用蛋白1(protein interacting with Cαkinase 1,PICK1)是衔接膜上受体和蛋白激酶Cα的重要蛋白.利用荧光光谱结合定点突变技术、蛋白与脂质覆盖法等方法,分析了PICK1蛋白N末端区域几个酸性氨基酸残基对PDZ结构域与膜脂结合的影响,以及钙离子结合N末端酸性区域对PDZ脂结合能力的调节.结果显示,带有上游酸性区域的PDZ结构域(NPDZ)的脂质结合能力仅相当PDZ结构域的15%,相比单独的PDZ结构域与脂质的解离常数Kd(PDZ)为1.58×103μg.L-1,NPDZ与脂质解离常数Kd(NPDZ)为3.3×104μg.L-1,其中在N末端酸性残基中D8与D12两个天冬氨酸是影响脂质结合能力减弱的关键残基,若将二者分别突变为丙氨酸后,NPDZ与脂质的解离常数分别为:Kd(D8/A)=4.42×103μg.L-1;Kd(D12/A)=1.73×103μg.L-1接近于PDZ结构域与脂质结合能力;钙离子会增强NPDZ脂结合能力,当钙离子浓度达到30μmol/L时,NPDZ的脂结合能力提高2.3倍,但只相当于PDZ的50%的结合能力.Protein interacting with Cot kinase 1 （ PICK1 ）, plays an important role in linking the membrane receptors and PKCct in synapse. We have analyzed the interaction between the PDZ domain and membrane lipid regulated by its adjacent N-terminal acid region, using fluorescence spectra, gene manipulation combined with PLO （protein-lipid overlay assay）. The result indicated that N-terminal acid region of PICK1 decreased the interaction between PDZ domain of PICK1 and membrane lipid about 85% degree. D8, D12 of N-terminal acidic regions constitute the key residues for decreasing PDZ binding to lipid. 30 /mol/L Ca2＋ could enhance the lipid binding ability of PDZ domain with its adjacent N-terminal acid region about 2.3 times, but that was about 50% degree compared to that of only PDZ domain.

关 键 词：PDZ结构域 N端酸性区域 脂质体 荧光光谱 CA2+ 

分 类 号：Q71[生物学—分子生物学]