The interaction of cordycepin with calf thymus DNA was investigated at physiological pH with drug/DNA molar ratio of 8. The Raman spectroscopy results indicated that the intercalation of high concentration c...The interaction of cordycepin with calf thymus DNA was investigated at physiological pH with drug/DNA molar ratio of 8. The Raman spectroscopy results indicated that the intercalation of high concentration cordycepin and the interaction of cordycepin with PO2 group led to a major reduction of B-form DNA structure in favor of A-form DNA.展开更多
在p H 7.4的生理条件下,以溴化乙锭(EB)作为荧光探针,利用荧光光谱、紫外-可见吸收光谱、共振散射光谱法结合盐效应和DNA熔点(T_m)实验研究了柯里拉京(Cor)与小牛胸腺DNA分子之间的相互作用机制。实验结果表明,Cor静态猝灭DNA-EB体系的...在p H 7.4的生理条件下,以溴化乙锭(EB)作为荧光探针,利用荧光光谱、紫外-可见吸收光谱、共振散射光谱法结合盐效应和DNA熔点(T_m)实验研究了柯里拉京(Cor)与小牛胸腺DNA分子之间的相互作用机制。实验结果表明,Cor静态猝灭DNA-EB体系的荧光。Cor与DNA作用后,其特征吸收峰强度发生减色效应;与DNA作用导致Cor在480.5 nm处的共振散射峰增强,并在330.2 nm处出现新共振散射峰。盐效应对Cor与DNA分子相互作用的影响较小。与Cor作用引起DNA的T_m值升高5.5℃。由此推断,Cor与DNA相互作用的主要方式为嵌插,两者间形成了超分子体系。通过计算获得Cor与DNA间结合常数(K_A)为5.82×10~3L/mol(298 K)、2.47×10~4L/mol(310 K),它们之间的作用为熵驱动的自发、吸热过程,疏水作用力是主要的非共价作用方式。展开更多
Hypocrellin B (HB) is a highly effective photosensitizer. One of its derivatives, 5_brominated_hypocrellin B (5_Br_HB) has better photosensitive characteristics than it. Using Raman spectroscopy, the microcosmic photo...Hypocrellin B (HB) is a highly effective photosensitizer. One of its derivatives, 5_brominated_hypocrellin B (5_Br_HB) has better photosensitive characteristics than it. Using Raman spectroscopy, the microcosmic photodamage to DNA sensitized by HB and 5_Br_HB was studied at molecular level. The results showed that when HB and 5_Br_HB were added to the solution of DNA and irradiated, the characteristic Raman frequencies and intensities of DNA changed to various degrees. The photodamage occurred on the whole DNA molecule, including phosphate backbone,deoxyribose and four bases. Not only the conformation but also the configuration of DNA was photodamaged: breakage of some H_bonds, disappearance of B_form conformation , scission of double or single strand and serious damage of four bases. The damage to A_T pairs was stronger than that to C_G pairs and DNA became polynucleotides finally. The 5_Br_HB_photosensitized damage to DNA was stronger than HB , which suggested the better photosensitive characteristics of 5_Br_HB in bioactive environment. The molecular mechanisms of photodamage to DNA sensitized by 5_Br_HB and HB were also elucidated.展开更多
基金Project 3037014 was supported by the National Natural Science Foundation of China
文摘The interaction of cordycepin with calf thymus DNA was investigated at physiological pH with drug/DNA molar ratio of 8. The Raman spectroscopy results indicated that the intercalation of high concentration cordycepin and the interaction of cordycepin with PO2 group led to a major reduction of B-form DNA structure in favor of A-form DNA.
文摘Hypocrellin B (HB) is a highly effective photosensitizer. One of its derivatives, 5_brominated_hypocrellin B (5_Br_HB) has better photosensitive characteristics than it. Using Raman spectroscopy, the microcosmic photodamage to DNA sensitized by HB and 5_Br_HB was studied at molecular level. The results showed that when HB and 5_Br_HB were added to the solution of DNA and irradiated, the characteristic Raman frequencies and intensities of DNA changed to various degrees. The photodamage occurred on the whole DNA molecule, including phosphate backbone,deoxyribose and four bases. Not only the conformation but also the configuration of DNA was photodamaged: breakage of some H_bonds, disappearance of B_form conformation , scission of double or single strand and serious damage of four bases. The damage to A_T pairs was stronger than that to C_G pairs and DNA became polynucleotides finally. The 5_Br_HB_photosensitized damage to DNA was stronger than HB , which suggested the better photosensitive characteristics of 5_Br_HB in bioactive environment. The molecular mechanisms of photodamage to DNA sensitized by 5_Br_HB and HB were also elucidated.
