Ohana B, Gershoni J M
Department of Biophysics, Weizmann Institute of Science, Rehovot, Israel.
Biochemistry. 1990 Jul 10;29(27):6409-15. doi: 10.1021/bi00479a011.
Recombinant toxin binding proteins have been previously found to provide a convenient experimental system for the study of receptor-ligand recognition (Aronheim et al., 1988). Here, this system has been used to produce the binding sites of the cholinergic receptor derived from seven organisms, Torpedo californica, Xenopus, chick, mouse, calf, human, and Drosophila. These have been compared with respect to their toxin binding capacity. Scatchard analyses show that the KD values of alpha-bungarotoxin binding to the above sites are 63, 536, 150, 3200, 6200, 6470, and 1700 nM, respectively. These results reiterate the importance of alpha 183-204 as a ligand binding site. In order to increase the repertoire of sites available for study, chimeric structures were constructed. Through the analysis of such chimeras, some themes of the gross anatomy of the binding site can be learned. A positive subsite followed by a hydrophobic patch preceding a nucleophilic domain appears to be required for efficient toxin binding.
重组毒素结合蛋白此前已被发现可为受体-配体识别研究提供一个便利的实验系统（阿罗海姆等人，1988年）。在此，该系统已被用于制备源自七种生物（加州电鳐、非洲爪蟾、鸡、小鼠、小牛、人类和果蝇）的胆碱能受体的结合位点。已对这些结合位点的毒素结合能力进行了比较。斯卡查德分析表明，α-银环蛇毒素与上述位点结合的KD值分别为63、536、150、3200、6200、6470和1700 nM。这些结果再次强调了α183 - 204作为配体结合位点的重要性。为了增加可供研究的位点种类，构建了嵌合结构。通过对这类嵌合体的分析，可以了解结合位点总体结构的一些规律。高效毒素结合似乎需要一个正性子位点，其后是一个疏水区域，再前面是一个亲核结构域。
