酵母酸性磷酸酯酶转录调控因子PHO2的功能域分析  

Studies on the Function Domains of the Transcriptional Requlatory Factor PHO2 in Yeast Acid Phosphatase System

作　　者：杨军[1] 吴健生[1] 敖世洲[1] 

机构地区：[1]中国科学院上海生物化学研究所分子生物学国家重点实验室

出　　处：《生物化学与生物物理学报》1995年第2期165-171,共7页

摘　　要：利用定点诱变，氨基酸插入或缺失的方法对ＰＨＯ２进行结构改造，观察对其功能的影响。ＰＨＯ２蛋白的同源域中有α－螺旋２－β－转角－α螺旋３的结构，是转录因子结合ＤＮＡ的功能域。定点诱变α－螺旋３上的Ｉｌｅ１２３为Ｐｒｏ１２３．或者在α－螺旋２中插入ＰＤＰＤ４个氨基酸，破坏α－螺旋的结构，可导致ＰＨＯ２功能的丧失。氨基酸片段的缺失分析表明，Ｎ端Ｇｌｎ丰富区大部缺失，对ＰＨＯ２功能没有影响；而包含酸性氨基酸丰富区的第２６３～３６８位肽段的缺失，则导致ＰＨＯ２的失活。酸性区可能是ＰＨＯ２的转录激活功能域，在ＰＨＯ２的第２４１～２５８位肽段与ＰＨＯ８０第３２～５０肽段有５０％的同源性。它的缺失也使ＰＨＯ２失活，该区可能是ＰＨＯ２与ＰＨＯ４相作用的位点。Using site-directed mutagenesis insertion or deletion,PHO2 gene was changed in strueture, the effect of these changes on its funetion was observed.The homeodomain of PHO2 protein has such structure as a-helix 2-turn-a-helix 3,which acts as DNA binding domain of transcriptional factor,A site-driected mutant of Ile123 to Pro123 in a-helix 3 or insertion of four amino acids(PDPD) into a-helix 2 can destroy the a-helix structure, and lead to inaotivation of PHO2.Deletion analysis of the Gln-rich region of the N-terminal had no effect on PHO2 functions,while deletion of the acidic region(residue 249～261) inactivate the PHO2 protein These results show that the acidic region may act as a transpriptional activation domain of PHO2. A short cluster of residues(241～258) shared 50% homology with residues 32 to 50 of the negative factor WHO80 and deletion of this ragion inactivated the PHO2 protein.So we concluded that this region might be an association domain of PHO2 and PHO4 protein.

关 键 词：酵母 PHO2基因 酸性磷酸酯酶 转录 调控因子 

分 类 号：Q939.506[生物学—微生物学]