Bractoppin 是人 BRCA1 tBRCT 结构域识别磷酸肽的抑制剂，IC50 为 74 nM。
Bractoppin is a tandem BRCT (tandem BRCT, BRCA1) delivered by human breast and ovarian cancer suppressor protein (BRCA1) tBRCT domain recognizes a drug-like inhibitor of phosphopeptide that selectively inhibits nanomolar activity of substrate binding in vitro with an IC50 of 0.074 μM[1].
Bractoppin has nanomolar potency in displacing cognate BACH1 phosphopeptide substrate from the BRCA1 tBRCT. Its predicted binding mode to BRCA1 tBRCT reveals favorable hydrophobic interactions in the hydrophobic cavity, as well as a T-shaped, pi-pi stacking interaction with Phe1662, that together significantly contribute toward its activity. Indeed, substitution of the phenyl ring at R1 in Bractoppin with a 4-pyridyl group (CCBT2082) decreased activity by 5-fold by affecting the stacking interaction with Phe1662[1].
In cells, Bractoppin inhibits substrate recognition detected by F?rster resonance energy transfer, and diminishes BRCA1 recruitment to DNA breaks, in turn suppressing damage-induced G2 arrest and assembly of the recombinase, RAD51[1].
参考文献:
[1]. Periasamy J, Kurdekar V, et,al. Targeting Phosphopeptide Recognition by the Human BRCA1 Tandem BRCT Domain to Interrupt BRCA1-Dependent Signaling. Cell Chem Biol. 2018 Jun 21;25(6):677-690.e12. doi: 10.1016/j.chembiol.2018.02.012. Epub 2018 Mar 29. PMID: 29606576; PMCID: PMC6015222.
Bractoppin 是一种串联 BRCT（串联 BRCT，BRCA1），由人乳腺癌和卵巢癌抑制蛋白 (BRCA1) tBRCT 结构域识别磷酸肽的药物样抑制剂，在体外选择性抑制底物结合的纳摩尔活性，IC50 为0.074 77777#181;M[1]。
Bractoppin 在从 BRCA1 tBRCT 中置换同源 BACH1 磷酸肽底物方面具有纳摩尔效力。它与 BRCA1 tBRCT 的预测结合模式揭示了疏水腔中有利的疏水相互作用，以及与 Phe1662 的 T 形 pi-pi 堆叠相互作用，这些共同显着促进了其活性。实际上，用 4-吡啶基取代 Bractoppin 中 R1 的苯环 (CCBT2082) 通过影响与 Phe1662[1] 的堆积相互作用，使活性降低了 5 倍。
在细胞中，Bractoppin 抑制由 FÖ 检测到的底物识别；rster 共振能量转移，并减少 BRCA1 募集到 DNA 断裂，进而抑制损伤诱导的 G2 停滞和重组酶 RAD51[1] 的组装.
| Kinase experiment [1]: | |
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Preparation Method |
For the direct binding assay, 10μl of labeled protein at a final concentration of 20nM was mixed with 10μl of test compound( Bractoppin ) and incubated on ice for 10 min. For the competitive assay, 10μl of labeled protein at a final concentration of 20nM was mixed with 2μM cognate peptide substrate at the EC80 concentration determined by prior titration using a 16-point serial dilution by direct-binding MST. |
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Reaction Conditions |
0-105nM Bractoppin |
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Applications |
Bractoppin is a 414-Da compound, with nanomolar potency in displacing cognate BACH1 phosphopeptide substrate from the BRCA1 tBRCT as measured by MST（ IC50 0.074 μM）. Its predicted binding mode to BRCA1 tBRCT reveals favorable hydrophobic interactions in the hydrophobic cavity, as well as a T-shaped, pi-pi stacking interaction with Phe1662, that together significantly contribute toward its activity. Indeed, substitution of the phenyl ring at R1 in Bractoppin with a 4-pyridyl group (CCBT2082) decreased activity by 5-fold by affecting the stacking interaction with Phe1662. |
| Cell experiment [2]: | |
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Cell lines |
HEK293 cells |
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Preparation Method |
HEK293 cells stably harboring plasmids for Tet-inducible expression of tBRCT domains were seeded. Compound( Bractoppin )addition or inducible expression of BRCA1 tBRCT were performed as indicated, when cells were 30% confluent, before exposure to 1Gy irradiation. |
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Reaction Conditions |
1-100uM Bractoppin for 7 days |
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Applications |
In cells, Bractoppin inhibits substrate recognition detected by F?rster resonance energy transfer, and diminishes BRCA1 recruitment to DNA breaks, in turn suppressing damage-induced G2 arrest and assembly of the recombinase, RAD51. |
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参考文献: [1]. Periasamy J, Kurdekar V, et,al.Targeting Phosphopeptide Recognition by the Human BRCA1 Tandem BRCT Domain to Interrupt BRCA1-Dependent Signaling. Cell Chem Biol. 2018 Jun 21;25(6):677-690.e12. doi: 10.1016/j.chembiol.2018.02.012. Epub 2018 Mar 29. PMID: 29606576; PMCID: PMC6015222. |
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