摘要
绿脓杆菌外毒素A有三个结构功能区。氨基端区(Ⅰ)通过关键位点Lys57结合靶细胞表面受体。中心区(Ⅱ)负责该毒素的跨膜转位功能,Arg276和Arg279是关键位点.在胞吞泡内此毒素于Arg279与Gly280间酶解成28000和37000两片段。羧基端区(Ⅲ)所在的37000片段由其末端氨基酸序列REDLK介导到内质网再转位入胞浆通过Glu553位点结合NAD ̄+使延伸因子-2受ADP-核糖基化而抑制细胞蛋白质合成导致细胞死亡。改造的毒素基因同识别蛋白基因融合成的重组毒素有应用前景。
Pseudomonas aeruginosa exotoxinA(PE)contains three structure function do-mains. The amino-terminal domain Ⅰ is in-volved in binding to target cell-surface recep-tors through the active site Lys57.The cen-tral domain Ⅱ is responsible for the transloca-tion of PE across membranes,Arg276 andArg279 are the active key positions of the do-main Ⅱ.The protease cleaves PE betweenArg279 and Gly280 into 28 000 and 37 000fragments. The carboxyl-terminal domain Ⅲis located in 37 000 fragment which is directedby the REDLK sequence at the carboxyl endof domain Ⅲ to the endoplasmic reticulum andtranslocated to the cytosol,and then ADP-ri-bosylates the EF-2(elongation factor 2)bybinding NAD ̄+ through the key site Glu553 toresult in the inhibition of cell protein synthesisand death of target cells.It is a practicalprospect that the recombinant immunotoxinsare made by fusing DNA fragments encodingrecognition proteins to the modified PE genes.
出处
《生物化学与生物物理进展》
SCIE
CAS
CSCD
北大核心
1995年第2期112-117,共6页
Progress In Biochemistry and Biophysics
关键词
绿脓杆菌
外毒素A
重组毒素
pseudomonas aeruginosa exotoxinA. immunotoxin,recombinant toxin