Conversion of a PI-anchored protein to an integral membrane protein by a single amino acid mutation.
Conversion of a PI-anchored protein to an integral membrane protein by a single amino acid mutation.
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通过单个氨基酸突变将 PI 锚定蛋白转化为完整膜蛋白。
DOI：
10.1126/science.3399901
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Flavell,RA
中科院分区：
文献类型：
--
作者：
Waneck,GL;Stein,ME;Flavell,RA
QA-2是一种由磷脂酰肌醇(PI)锚定的细胞表面糖蛋白，在结构上与I类移植抗原H-2K、D和L有关，它们是完整的膜糖蛋白。预测的Qa-2跨膜片段与H-2K、D和L的跨膜片段不同，因为在第295位存在天冬氨酸而不是valine。用Valine取代天冬氨酸的单一碱基改变导致细胞表面的Qa-2分子对PI专一性磷脂酶C的水解不敏感，并且更耐木瓜酶切割，这是H-2D所共有的特性。表达天冬氨酸→Val突变Qa-2蛋白的细胞仍能与内源性蛋白如Thy-1和J11D结合PI锚点。因此，这种单一的氨基酸变化似乎将Qa-2从PI连接的形式转换为完整的膜蛋白。
Qa-2, a cell-surface glycoprotein anchored by phosphatidylinositol (PI), is structurally related to the class I transplantation antigens H-2 K, D, and L, which are integral membrane glycoproteins. The predicted transmembrane segment of Qa-2 differs from those of H-2 K, D, and L by the presence of an aspartate in place of a valine at position 295. A single base change that replaced this aspartate with valine resulted in cell-surface Qa-2 molecules that were insensitive to hydrolysis by a PI-specific phospholipase C and more resistant to papain cleavage, properties shared by H-2D. Cells expressing Asp → Val mutant Qa-2 proteins were still able to attach a PI anchor to endogenous proteins such as Thy-1 and J11D. It therefore appears that this single amino acid change converts Qa-2 from a PI-linked form into an integral membrane protein.