Department of Biochemistry, School of Medicine, University of Alberta, Edmonton, AB, Canada.
Biochemistry. 2011 May 31;50(21):4579-89. doi: 10.1021/bi2003795. Epub 2011 May 10.
The BRCA1 BRCT domain binds pSer-x-x-Phe motifs in partner proteins to regulate the cellular response to DNA damage. Approximately 120 distinct missense variants have been identified in the BRCA1 BRCT through breast cancer screening, and several of these have been linked to an increased cancer risk. Here we probe the structures and peptide-binding activities of variants that affect the BRCA1 BRCT phosphopeptide-binding groove. The results obtained from the G1656D and T1700A variants illustrate the role of Ser1655 in pSer recognition. Mutations at Arg1699 (R1699W and R1699Q) significantly reduce peptide binding through loss of contacts to the main chain of the Phe(+3) residue and, in the case of R1699W, to a destabilization of the BRCT fold. The R1835P and E1836K variants do not dramatically reduce peptide binding, in spite of the fact that these mutations significantly alter the structure of the walls of the Phe(+3) pocket.
BRCA1 BRCT 结构域与伴侣蛋白中的 pSer-x-x-Phe 基序结合，以调节细胞对 DNA 损伤的反应。通过乳腺癌筛查，在 BRCA1 BRCT 中已经鉴定出大约 120 种不同的错义变体，其中一些与癌症风险增加有关。在这里，我们研究了影响 BRCA1 BRCT 磷酸肽结合槽的变体的结构和肽结合活性。来自 G1656D 和 T1700A 变体的结果说明了 Ser1655 在 pSer 识别中的作用。Arg1699 处的突变（R1699W 和 R1699Q）通过与 Phe(+3)残基的主链失去接触，以及在 R1699W 的情况下，破坏 BRCT 折叠，显著降低了肽的结合。R1835P 和 E1836K 变体并没有显著降低肽的结合，尽管这些突变显著改变了 Phe(+3)口袋壁的结构。
