Dss1 regulates interaction of Brh2 with DNA

Qingwen Zhou, Nayef Mazloum, Ninghui Mao, Milorad Kojic, William K. Holloman

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Brh2, the BRCA2 homologue in Ustilago maydis, plays a crucial role in homologous recombination by controlling Rad51. In turn, Brh2 is governed by Dss1, an intrinsically disordered protein that forms a tight complex with the C-terminal region of Brh2. This region of the protein associating with Dss1 is highly conserved in sequence and by comparison with mammalian BRCA2 corresponds to a part of the DNA binding domain with characteristic OB folds. The N-terminal region of Brh2 harbors a less-defined but powerful DNA binding site, the activity of which is revealed upon deletion of the C-terminal region. Full-length Brh2 complexed with Dss1 binds DNA slowly, while the N-terminal fragment binds quickly. The DNA binding activity of full-length Brh2 appears to correlate with dissociation of Dss1. Addition of Dss1 to the heterotypic Brh2-Dss1 complex attenuates DNA binding activity, but not by direct competition for the N-terminal DNA binding site. Conversely, the Brh2-Dss1 complex dissociates more quickly when DNA is present. These findings suggest a model in which binding of Brh2 toDNA is subject to allosteric regulation by Dss1.

Original languageEnglish
Pages (from-to)11929-11938
Number of pages10
Issue number50
Publication statusPublished - 22 Dec 2009


ASJC Scopus subject areas

  • Biochemistry

Cite this

Zhou, Q., Mazloum, N., Mao, N., Kojic, M., & Holloman, W. K. (2009). Dss1 regulates interaction of Brh2 with DNA. Biochemistry, 48(50), 11929-11938. https://doi.org/10.1021/bi901775j