Dss1 Regulates Interaction of Brh2 with DNA

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• 作者：Qingwen Zhou ; Nayef Mazloum ; Ninghui Mao ; Milorad Kojic ; William K. Holloman
• 刊名：Biochemistry
• 出版年：2009
• 出版时间：December 22, 2009
• 年：2009
• 卷：48
• 期：50
• 页码：11929-11938
• 全文大小：1041K
• 年卷期：v.48,no.50(December 22, 2009)
• ISSN：1520-4995

文摘

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 to DNA is subject to allosteric regulation by Dss1.