Proteins containing the Rel homology domain (RHD) are eukaryotic transcription factors. The RHD is composed of two structural domains. This is the N-terminal DNA-binding domain that is similar to that found in P53. The C-terminal domain has an immunoglobulin-like fold (See Pfam:PF16179) that functions as a dimerisation domain [1-2].

1: Structure of the NF-kappa B p50 homodimer bound to DNA. Muller CW, Rey FA, Sodeoka M, Verdine GL, Harrison SC; Nature 1995;373:311-317. PMID:7830764

2: X-ray structure of a NF-kappaB p50/RelB/DNA complex reveals assembly of multiple dimers on tandem kappaB sites. Moorthy AK, Huang DB, Wang VY, Vu D, Ghosh G; J Mol Biol. 2007;373:723-734. PMID:17869269