Chemical biology of molecular interaction between tea catechins with biological substances

1.由石英晶体微天平(QCM)频率变化得到的结合常数表明，ECG和EGCG与HSA的相互作用是EC和EGC2的100倍。2.茶儿茶素在HSA中形成蛋白质羰基的最重要的结构单元是B环上的邻苯三酚结构基元，其次是没食子酸基。通过质谱学和氧化还原循环染色的凝胶/印迹分析，我们发现邻苯三酚类儿茶素与蛋白质硫醇的反应活性高于儿茶酚类儿茶素。3.合成了没食子酸基上的13&gt；C同位素标记的没食子酰基的[^&lt；13&gt；C]-ecg，并进行了固体核磁共振谱分析。固态核磁共振分析表明，心电改变了DMPC双层膜的凝胶-液晶相变温度以及磷脂的动力学和迁移性。准确的分子间。通过旋转回波双共振(REDOR)测量，测得标记的[13&gt；13&gt；C]-ecg上的羰基碳与磷脂的原子间距为5.3±0.1A。4.在多种肿瘤细胞中过表达的死盒RNA解旋酶p68被鉴定为一个新的EGCG结合靶点。

1.The association constants obtained from the frequency changes of quartz-crystal microbalance(QCM) revealed interactions of ECg and EGCg with HSA that are 100 times stronger than those of EC and EGC.2.The most important structural element contributing to the formation of protein carbonyl in HSA by tea catechins is the pyrogallol structural motif in the B-ring, followed by the galloyl group. By both mass spectrometry and electrophoresis/blotting with redox-cycling staining, we revealed that pyrogallol-type catechins had higher reactivity with protein thiols than catechol-type catechins.3.We synthesized[^<13> C]-ECg, in which the carbonyl carbon of the galloyl moiety was labeled by^<13> C isotope, and analyzed it by solid-state NMR spectroscopy. Solid-state^<31> P NMR analysis indicated that ECg changes the gel-to-liquid-crystalline phase transition temperature of DMPC bilayers as well as the dynamics and mobility of the phospholipids. The accurate intermolecular. interatomic distance between the labeled carbonyl carbon of[^<13> C]-ECg and the phosphorus of the phospholipid was determined to be 5.3±0.1 A by^<13> C.^<31> P rotational echo double resonance(REDOR) measurements.4.The DEAD-box RNA helicase p68, which is overexpressed in a variety of tumor cells and plays an important role in cancer development and progression, was identified as a novel EGCG-binding target.