二氢杨梅素对Bloom解旋酶结构和生物学活性的影响

目的二氢杨梅素(dihydromyricetin,DMY),是一种黄酮类化合物,具有抗炎、抗肿瘤等作用,研究DMY对Bloom解旋酶(Bloom helicase,BLM)生物学活性的影响对探索DMY的抗肿瘤机制具有重要意义。方法采用紫外光谱、圆二色谱、荧光偏振和自由磷检测等方法和技术研究DMY对BLM解旋酶的生物学活性的影响。结果圆二色谱和紫外光谱结果显示,DMY能与BLM解旋酶结合,且有1个结合位点;在0~25μmol·L^-1浓度范围内,DMY对BLM解旋酶的二级结构的干扰能力成正相关,在25~75μmol·L^-1浓度范围内则相反。荧光偏振和自由磷检测实验显示,DMY能结合在BLM解旋酶上,进而抑制BLM解旋酶的解链活性。结论DMY能够竞争性结合于BLM解旋酶的DNA结合位点上,改变BLM解旋酶的空间结构,从而抑制BLM解旋酶与DNA的结合,进而抑制BLM解旋酶的生物学活性。

Effects of dihydromyricetin on biological properties of Bloom syndrome helicase

Aim To explore the anti-tumor mechanism of dihydromyricetin(DMY),a kind of flavonoid compound with anti-inflammatory and anti-tumor effects,via studying the effect of DMY on biological activities of Bloom helicase.Methods The effect of DMY on the biological activities of BLM helicase was studied by ultraviolet spectrum(UV),circular dichroism(CD),fluorescence polarization and free phosphorus detection.Results The results of CD and UV showed that DMY could bind to a site of the BLM helicase.In the concentration of DMY in 0~25 μmol·L^-1 range,DMY showed a positive correlation with the interference ability of BLM helicase secondary structure with the increase of concentration,while in the concentration of DMY in 25~75 μmol·L^-1 range,DMY showed a negative correlation.Fluorescence polarization and free phosphorus detection experiments showed that DMY could bind to BLM helicase,thus inhibiting the helicase activity of BLM helicase.Conclusions DMY can competitively bind to the DNA binding site of BLM helicase and change the spatial structure of BLM helicase,inhibiting the binding of BLM helicase to DNA and the biological activity of BLM helicase accordingly.