Crystal structure of an OCA-B peptide bound to an Oct-1 POU domain/octamer DNA complex: specific recognition of a protein-DNA interface.Chasman, D., Cepek, K., Sharp, P.A., Pabo, C.O.
(1999) Genes Dev 13: 2650-2657
- PubMed: 10541551
- DOI: https://doi.org/10.1101/gad.13.20.2650
- Primary Citation of Related Structures:
- PubMed Abstract:
We have determined the crystal structure, at 3.2 A, of a ternary complex containing an OCA-B peptide, the Oct-1 POU domain, and an octamer DNA site. The OCA-B peptide binds in the major groove near the center of the octamer site, and its polypeptide backbone forms a pair of hydrogen bonds with the adenine base at position 5 of the octamer DNA. Numerous protein-protein contacts between the OCA-B peptide and the POU domain are also involved in the ternary complex. In particular, the hydrophobic surface from a short alpha-helix of OCA-B helps to stabilize the complex by binding to a hydrophobic pocket on the POU-specific domain. The structure of this ternary complex is consistent with previous biochemical studies and shows how peptide-DNA and peptide-protein contacts from OCA-B provide structural and functional specificity in the regulation of immunoglobulin transcription.
Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.