摘要
苏云金芽胞杆菌 (Bacillusthuringiensis)杀虫晶体蛋白的毒性肽由三个典型的结构域组成 .结构域Ⅰ位于肽链的N端 ,为一组由 6～ 7个两亲的α螺旋围绕着一个疏水的α螺旋形成的α螺旋束 ,参与了细胞膜的穿孔 ;结构域Ⅱ位于肽链的中间 ,为三组以“希腊钥匙” (Greekkey)拓扑结构连接在一起的反平行的 β折叠片层 ,其顶端的突环参与了毒素与受体蛋白的结合 ;位于C端的结构域Ⅲ是由两组反平行的 β折叠片层组成的夹心结构 ,以 β果酱卷 (jellyroll)拓扑结构排列 。
Three dimensional structure of insecticidal crystal proteins of Bacillus thuringiensis has been revealed to be three distinct domains. It has been found that different Cry toxins share similar structures. Domain Ⅰ, consisting of a bundle of α helices in which a hydrophobic helix 5 is surrounded by 6～7 amphipathic helices, plays a unique role in pore formation. Domain Ⅱ, consisting of three antiparallel β sheets with a loop at each apex, is responsible for receptor binding. Domain Ⅲ consists of two twisted, antiparallel β sheets forming aβ sandwich with a “jelly roll” topology, it might prevent the activated toxin from excessive degradation.
出处
《生物化学与生物物理进展》
SCIE
CAS
CSCD
北大核心
2000年第5期476-480,共5页
Progress In Biochemistry and Biophysics
