Structural studies of the post-cleavage complex in V(D)J recombination

虽然RAG1和RAG2蛋白的生物化学信息很多，但目前还没有相关的结构数据。作为该小组先前工作的结果，我们鉴定了该系统中定义最好且最稳定的复合物，其为在重组位点切割DNA后具有两个DNA末端的复合物RAG1和RAG2。这种复合物现在已经制备了足够的高分辨率电子显微镜。与Wei Yang博士（LMB）和Alasdair Steven博士（NIAMS）的合作安排首次产生了足以用于图像重建的负染色样本的照片，显示了中空核心和其他定义特征的证据。目前的努力集中在更高的分辨率，可以获得冷冻电子显微镜和免疫电子显微镜，结合分子量估计扫描透射电子显微镜。与生物物理测量一起，结果已经澄清了在文献中一直存在争议的复合物的蛋白质化学计量的问题。蛋白质制备方法的进一步放大也可以允许复合物的结晶。

Although there is a great deal of biochemical information about the RAG1and RAG2 proteins, no correlated structural data exist so far. As a result of previous work from this group, we identified the best-defined and most stable complex in this system as being the complex RAG1 and RAG2 make with two DNA ends after cutting DNA at the recombination sites. This complex has now been prepared in sufficient quantity for high-resolution electron microscopy. A collaborative arrangement with the groups of Dr. Wei Yang (LMB) and Dr. Alasdair Steven (NIAMS) has produced for the first time pictures of negatively stained samples good enough for image reconstruction, which shows evidence of a hollow core and other defined features. Present efforts focus on higher resolution that can be obtained with cryo-electron microscopy and immuno-electron microscopy, to be combined with molecular weight estimation by scanning transmission electron microscopy. Together with biophysical measurements, the results have already clarified the issue of the protein stoichiometry of the complex, which has been in dispute in the literature. Further scaling up of the protein preparation method may also permit crystallization of the complex.