Clark R, Wong G, Arnheim N, Nitecki D, McCormick F
Proc Natl Acad Sci U S A. 1985 Aug;82(16):5280-4. doi: 10.1073/pnas.82.16.5280.
An antibody (anti-p21ser) was raised against a ras p21-related synthetic peptide and was able to recognize specifically the substitution of serine for glycine at amino acid 12 of p21. This substitution causes oncogenic activation of p21. Anti-p21ser was found to immunoprecipitate v-Ki-ras p21 and to strongly inhibit its ability to autophosphorylate and to bind GTP in an immunoabsorption assay. Furthermore, binding of the antibody to p21 was specifically inhibited by GTP or GDP, suggesting that amino acids around position 12 are part of the GTP/GDP binding site. These results, taken together with the observation that the microinjection of anti-p21ser into cells transformed by v-Ki-ras p21 causes a transient reversion of the cells to a normal phenotype [Feramisco, J. R., Clark, R., Wong, G., Arnheim, N., Milley, R. & McCormick, F. (1985) Nature (London) 314, 639-642], support the idea that interaction of p21 with guanine nucleotides is crucial to the transforming function of this protein.
针对一种与ras p21相关的合成肽制备了一种抗体（抗p21ser），该抗体能够特异性识别p21第12位氨基酸处丝氨酸取代甘氨酸的情况。这种取代会导致p21的致癌激活。在免疫吸附试验中，发现抗p21ser能免疫沉淀v-Ki-ras p21，并强烈抑制其自身磷酸化和结合GTP的能力。此外，GTP或GDP能特异性抑制该抗体与p21的结合，这表明12位附近的氨基酸是GTP/GDP结合位点的一部分。这些结果，再加上将抗p21ser显微注射到由v-Ki-ras p21转化的细胞中会导致细胞短暂恢复到正常表型的观察结果[费拉米斯科，J.R.，克拉克，R.，王，G.，阿恩海姆，N.，米利，R.和麦科密克，F.（1985年）《自然》（伦敦）314，639 - 642]，支持了p21与鸟嘌呤核苷酸的相互作用对该蛋白的转化功能至关重要这一观点。
