Pepin M C, Beauchemin M, Collins C, Plamondon J, O'Connor-McCourt M D
Biotechnology Research Institute, National Research Council Canada, Montréal, Québec.
FEBS Lett. 1995 Dec 27;377(3):368-72. doi: 10.1016/0014-5793(95)01378-4.
There are two TGF-beta binding subdomains in the extracellular domain of receptor type III (proximal and distal in relation to the transmembrane domain). Here we present an extension of our analysis of the proximal binding site of receptor type III. Due to the original deletion mutagenesis strategy, our proximal binding site contained 19 amino acids from the N-terminal part of the receptor. By deleting these, we demonstrated that they did not contribute to the binding ability of the proximal binding site. We also produced a soluble, secreted form of the proximal binding site and demonstrated that it was able to bind TGF-beta. Finally, we analyzed the role of the three asparagine residues (580, 591, 595) that are located in the region of the receptor that is necessary for expression of a functional proximal binding site, and found that mutation of these residues individually to alanine did not affect ligand binding.
III型受体的胞外结构域中有两个TGF-β结合亚结构域（相对于跨膜结构域分别为近端和远端）。在此，我们展示了对III型受体近端结合位点分析的扩展。由于最初的缺失诱变策略，我们的近端结合位点包含受体N端部分的19个氨基酸。通过删除这些氨基酸，我们证明它们对近端结合位点的结合能力没有贡献。我们还制备了近端结合位点的可溶性分泌形式，并证明它能够结合TGF-β。最后，我们分析了位于功能性近端结合位点表达所需的受体区域中的三个天冬酰胺残基（580、591、595）的作用，发现将这些残基分别突变为丙氨酸不会影响配体结合。
