Lacatena R M, Cellini A, Scavizzi F, Tocchini-Valentini G P
EniChem, Rome, Italy.
Proc Natl Acad Sci U S A. 1994 Oct 25;91(22):10521-5. doi: 10.1073/pnas.91.22.10521.
We have investigated the topology of the human beta 2-adrenergic receptor expressed in Escherichia coli, using the genetic method described by Beckwith and coworkers. We found that fusions with alkaline phosphatase beyond a certain point on the human beta 2-adrenergic receptor sequence were assembled into the bacterial membrane with the same topology as the human beta 2-adrenergic receptor in the mammalian membrane. The pattern that might have been expected on the basis of the topology of the human beta 2-adrenergic receptor in mammalian membranes was not reflected in the levels of alkaline phosphatase activity of the fusions occurring between the N-terminal region and positions close to the second external domain. Our data suggest that the correct positioning of the N terminus of the receptor depends on the presence of its C-terminal portions.
我们使用贝克威思及其同事所描述的遗传学方法，研究了在大肠杆菌中表达的人β2 - 肾上腺素能受体的拓扑结构。我们发现，在人β2 - 肾上腺素能受体序列上超过某一点与碱性磷酸酶的融合蛋白，以与哺乳动物膜中的人β2 - 肾上腺素能受体相同的拓扑结构组装到细菌膜中。基于哺乳动物膜中人β2 - 肾上腺素能受体的拓扑结构所预期的模式，并未反映在N端区域与靠近第二个外部结构域位置之间发生的融合蛋白的碱性磷酸酶活性水平上。我们的数据表明，受体N端的正确定位取决于其C端部分的存在。
