Crystal structure of the Bach1 BTB domain and its regulation of homodimerization

Nobutoshi Ito, Miki Watanabe-Matsui, Kazuhiko Igarashi, Kazutaka Murayama

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


The BTB/POZ domain is known as a protein-protein interaction motif that mediates homodimer and higher order self-associations. Proteins containing the BTB domain exist throughout eukaryotes; however, there is little information about the mechanism that determines the oligomeric state of the BTB domain. To address this question, we have determined the X-ray structure of the mouse Bach1 BTB domain. The present structure is similar to the previously determined BTB domain folds, including the human Bach1 BTB domain; however, distinct structural features are present, such as a novel homodimer interaction surface. The homodimer formation was found to involve a novel hydrogen bond network and interactions between hydrophobic surfaces of the kinked N-terminus (N-hook) and the partner's C-terminal residues. The deletion of the N-hook resulted in the conversion of the homodimer into a monomer in solution, indicating that the N-hook promotes the homodimerization of the mBach1 BTB domain. We have also found that the BTB domain of Bach2, a protein highly related to Bach1, is present as a monomer due to a short peptide insertion at the N-hook. These results represent the first example of the key modulatory element of BTB domain homodimerization.

Original languageEnglish
Pages (from-to)167-178
Number of pages12
JournalGenes to Cells
Issue number2
Publication statusPublished - 2009


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