Thompson Amanda J, Cronin Maureen S, Kirschner Daniel A
Biology Department, Boston College, Chestnut Hill, Massachusetts 02467-3811, USA.
J Neurosci Res. 2002 Mar 15;67(6):766-71. doi: 10.1002/jnr.10167.
Protein zero (P0) glycoprotein is the major integral membrane protein of the peripheral nervous system myelin in higher vertebrates. Previous findings indicate the formation of tetrameric assemblies from studies on isolated P0. To determine whether in intact myelin the P0 exists as oligomers, we isolated myelin from sciatic nerve of Xenopus laevis and analyzed it using sodium dodecyl sulfate and urea gel electrophoresis. P0 oligomerization was confirmed using Western blotting, which showed monomeric P0 at approximately 30 kDa and oligomeric P0 at approximately 60 kDa and approximately 120 kDa. A variety of denaturing conditions failed to convert any appreciable amount of oligomer to monomer. Instead, the addition of these denaturants further increased the amount of dimer and tetramer while decreasing the amount of monomer. Native gels showed dimeric P0 without the appearance of monomer or tetramer, suggesting that dimeric P0, the most prominent form of the protein, is the most stable and likely occurs in the native myelin membrane array.
蛋白零（P0）糖蛋白是高等脊椎动物外周神经系统髓磷脂的主要整合膜蛋白。先前的研究结果表明，通过对分离出的P0进行研究发现其能形成四聚体组装。为了确定在完整的髓磷脂中P0是否以寡聚体形式存在，我们从非洲爪蟾的坐骨神经中分离出髓磷脂，并使用十二烷基硫酸钠和尿素凝胶电泳对其进行分析。通过蛋白质印迹法证实了P0的寡聚化，该方法显示单体P0约为30 kDa，寡聚体P0约为60 kDa和120 kDa。各种变性条件都未能将任何可观量的寡聚体转化为单体。相反，添加这些变性剂进一步增加了二聚体和四聚体的量，同时减少了单体的量。非变性凝胶显示出二聚体P0，没有单体或四聚体出现，这表明二聚体P0是该蛋白最主要的形式，是最稳定的，并且可能存在于天然髓磷脂膜阵列中。
