RING finger, HC subclass, found in recombination activating gene-1 (RAG-1) and similar proteins
RAG-1, also known as V(D)J recombination-activating protein 1, RING finger protein 74 (RNF74), or endonuclease RAG1, is the catalytic component of the RAG complex, a multiprotein complex that mediates the DNA cleavage phase during V(D)J recombination. RAG1 is the lymphoid-specific factor that mediates the DNA-binding to the conserved recombination signal sequences (RSS) and catalyzes the DNA cleavage activities by introducing a double-strand break between the RSS and the adjacent coding segment. It also functions as an E3 ubiquitin-protein ligase that mediates monoubiquitination of histone H3, which is required for the joining step of V(D)J recombination. RAG-1 contains an N-terminal C3HC4-type RING-HC finger that mediates monoubiquitylation of Histone H3, an adjacent C2H2-type zinc finger, and a nonamer binding (NBD) DNA-binding domain.