The post-cleavage complex in V(D)J recombination

虽然rag1和RAG2蛋白的生化信息非常丰富，但目前还没有相关的结构数据。根据该小组之前的工作，我们确定了该系统中最明确和最稳定的复合体是RAG1和RAG2在重组位点切割DNA后与两个DNA末端形成的复合体。这种复合物现在已经制备了足够数量的高分辨率电子显微镜。与杨伟博士（LMB）和Alasdair Steven博士（NIAMS）团队的合作安排，首次制作了足以用于图像重建的负染色样品的图片，显示了空心核和其他明确特征的证据。目前的研究重点是通过低温电子显微镜和免疫电子显微镜获得更高的分辨率，并结合扫描透射电子显微镜的分子量估计。与生物物理测量一起，结果已经澄清了复合体的蛋白质化学计量问题，这在文献中一直存在争议。进一步扩大蛋白质制备方法也可以使该复合物结晶。

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.