Crystal structure of an OCA-B peptide bound to an Oct-1 POU domain/octamer DNA complex: specific recognition of a protein-DNA interface (original) (raw)

1. Daniel Chasman,
2. Karyn Cepek,
3. Phillip A. Sharp, and
4. Carl O. Pabo
5. Center for Cancer Research; Howard Hughes Medical Institute; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 USA

Abstract

We have determined the crystal structure, at 3.2 Å, 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 α-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.

• Oct-1
• POU domain
• OCA-B
• octamer
• crystal structure
• transcription
• immunoglobulin
• protein–DNA complex
• protein–DNA interface

Footnotes

• Present addresses: 4Variagenics, Inc., Cambridge, Massachusetts 02139 USA; 5Vertex Pharmaceuticals, Cambridge, Massachusetts 02139 USA.

• ↵Corresponding author.

• E-MAIL pabo{at}mit.edu; FAX (617) 253-8728.

• • Received June 29, 1999.
  • Accepted August 30, 1999.

• Cold Spring Harbor Laboratory Press

•