博莱霉素A₅与DNA结合序列特异性研究

博莱霉素A 5 与DNA结合序列特异性研究 SEQUENCE SELECTIVE BINDING OF BLEOMYCINA 5 TO DNA 李鹏 Li Peng 1 first-author 邹国林 Zou Guolin 1 武汉大学生命科学学院 武汉大学生命科学学院 College of Life Sciences,Wuhan University College of Life Sciences,Wuhan University 利用荧光淬灭法研究了博莱霉素Ａ５与小牛胸腺ＤＮＡ及ＤＮＡ类似物多聚ｄＧＣ、多聚ｄＡＴ的相互作用，其作用力为疏水作用及氢键，结合常数分别为０．５７×１０５，１．０７×１０５，０．４７×１０５ｍｏｌ－１Ｌ，每结合一个博莱霉素Ａ５所需碱基对数分别为２２～２３，５～６，２７～２８，上述结果表明博莱霉素Ａ５与ＤＮＡ的结合具有ＧＣ序列特异性 The binding of bleomycinA 5 to calf thymus DNA, poly（ dGdC） and poly （dAdT） was investigated by studying their effects on the fluorescence properties of bleomycin A 5.Quenching of bithiazole fluorescence by DNA was used to determine apparent equilibrium constants for the complex,which,in 50 mmol·L -1 Tris HCl buffer, pH8.2,are 0.57×10 5 mol·L -1 for calf thymus DNA,1.07×10 5 mol·L - 1 for poly （dGdC）and 0.47×10 5 mol·L -1 for poly（dAdT）.Calculating of binding energy suggests a partial intercalative binding mode via hydrophobic bond and hydrogen bond. Under these conditions,one molecule of bleomycinA 5 binds for every 22 to 23 base pairs in calf thymus DNA,5 to 6 base pairs in poly（dGdC） and 27 to 28 base pairs in poly（dAdT）. Apparently,binding of bleomycinA 5 to DNA perfers to GC sequence in DNA. 博莱霉素A5 DNA 序列特异性 荧光淬灭 bleomycinA 5 DNA sequence selectivity fluorescence quenching Q586 国家教委留学回国人员科研基金,湖北省自然科学基金 1996-06-01 2021-04-01 6