Brosig B, Langosch D
Universität Heidelberg, Neurobiologie Department, Germany.
Protein Sci. 1998 Apr;7(4):1052-6. doi: 10.1002/pro.5560070423.
The glycophorin A transmembrane segment homo-dimerizes to a right-handed pair of alpha-helices. Here, we identified the amino acid motif mediating this interaction within a natural membrane environment. Critical residues were grafted onto two different hydrophobic host sequences in a stepwise manner and self-assembly of the hybrid sequences was determined with the ToxR transcription activator system. Our results show that the motif LIxxGxxxGxxxT elicits a level of self-association equivalent to that of the original glycophorin A transmembrane segment. This motif is very similar to the one previously established in detergent solution. Interestingly, the central GxxxG motif by itself already induced strong self-assembly of host sequences and the three-residue spacing between both glycines proved to be optimal for the interaction. The GxxxG element thus appears to be the most crucial part of the interaction motif.
血型糖蛋白A跨膜区段同源二聚化为一对右手α螺旋。在此，我们在天然膜环境中鉴定出介导这种相互作用的氨基酸基序。关键残基以逐步的方式嫁接到两个不同的疏水宿主序列上，并使用ToxR转录激活系统确定杂合序列的自组装情况。我们的结果表明，基序LIxxGxxxGxxxT引发的自缔合水平与原始血型糖蛋白A跨膜区段相当。该基序与先前在去污剂溶液中确定的基序非常相似。有趣的是，中央GxxxG基序本身就已经诱导了宿主序列的强烈自组装，并且两个甘氨酸之间的三个残基间距被证明是相互作用的最佳间距。因此，GxxxG元件似乎是相互作用基序中最关键的部分。
