Crystal structure of the V(D)J recombinase RAG1-RAG2..     ///    Here we report the crystal structure of the mouse RAG1-RAG2 complex at 3.2?? resolution.     ///    "The RAG1-RAG2 structure rationalizes more than 60 mutations identified in immunodeficient patients, as well as a large body of genetic and biochemical data. "    ///    The RAG1-RAG2 protein complex initiates this site-specific recombination by cutting DNA at specific sites flanking the coding segments.     ///    "The 230-kilodalton RAG1-RAG2 heterotetramer is 'Y-shaped', with the amino-terminal domains of the two RAG1 chains forming an intertwined stalk. "    ///    "Each RAG1-RAG2 heterodimer composes one arm of the 'Y', with the active site in the middle and RAG2 at its tip. "