STRUCTURE OF THE NF-KAPPA-B P50 HOMODIMER BOUND TO DNA

The structure of a large fragment of the p50 subunit of the human tran scription factor NF-kappa B, bound as a homodimer to DNA, reveals that the Rel-homology region has two beta-barrel domains that grip DNA in the major groove. Both domains contact the DNA backbone. The amino-ter minal specificity domain contains a recognition loop that interacts wi th DNA bases; the carboxy-terminal dimerization domain bears the site of I-kappa B interaction. The folds of these domains are related to im munoglobulin-like modules. The amino-terminal domain also resembles th e core domain of p53.