Netropsin . dG-dG-dA-dA-dT-dT-dC-dC complex. Antibiotic binding at adenine . thymine base pairs in the minor groove of the self-complementary octanucleotide duplex.
Netropsin . dG-dG-dA-dA-dT-dT-dC-dC complex. Antibiotic binding at adenine . thymine base pairs in the minor groove of the self-complementary octanucleotide duplex.
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内托普辛。
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发表时间：
1979
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通讯作者：
D. Patel
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作者：
D. Patel
netropsin的结构。dG-dG-dA-dA-dT-dT-dC-dC复合物（一个抗生素分子/自互补的octanucleodide双链体）及其作为温度的函数的动力学已经通过Watson-Crick质子、不可交换的碱和糖质子以及骨架磷酸的核磁共振来监测。抗生素在dA处与核酸双链体形成复合物。含dT的四核苷酸片段dA-dA-dT-dT，在低温下在潜在结合位点之间缓慢迁移。在复合物形成的netropsin的可交换质子的低场位移证明了抗生素和核酸之间的氢键相互作用对复合物的稳定性的贡献。复合物的形成导致胸苷残基和一个脱氧腺苷残基的糖苷扭转角的变化，如通过胸腺嘧啶C-6和腺嘌呤C-8质子的化学位移变化所监测的。抗生素的吡咯环和小沟中碱基对边缘的紧密接近表现在复合物形成时netropsin的吡咯C-3质子和一个腺嘌呤C-2质子和一个胸腺嘧啶N-3碱基对质子的低场位移（0.3--0.5ppm）。八核苷酸的核苷酸间磷酸盐在添加netropsin时经历31 P化学位移变化，并且这些可能部分反映了抗生素的带电末端与核酸的骨架磷酸盐之间的静电相互作用的贡献。
The structure of the netropsin . dG-dG-dA-dA-dT-dT-dC-dC complex (one antibiotic molecule/self-complementary octanucleodide duplex) and its dynamics as a function of temperature have been monitored by the nuclear magnetic resonances of the Watson-Crick protons, the nonexchangeable base and sugar protons and the backbone phosphates. The antibiotic forms a complex with the nucleic acid duplex at the dA . dT-containing tetranucleotide segment dA-dA-dT-dT, with slow migration amongst potential binding sites at low temperature. The downfield shifts in the exchangeable protons of netropsin on complex formation demonstrate the contributions of hydrogen-bonding interactions between the antibiotic and the nucleic acid to the stability of the complex. Complex formation results in changes in the glycosidic torsion angles of both thymidine residues and one deoxyadenosine residue as monitored by chemical shift changes in the thymine C-6 and adenine C-8 protons. The close proximity of the pyrrole rings of the antibiotic and the base-pair edges in the minor groove is manifested in the downfield shifts (0.3--0.5 ppm) of the pyrrole C-3 protons of netropsin and one adenine C-2 proton and one thymine N-3 base-pair proton on complex formation. The internucleotide phosphates of the octanucleotide undergo 31P chemical shift changes on addition of netropsin and these may reflect, in part, contributions from electrostatic interactions between the charged ends of the antibiotic and the backbone phosphates of the nucleic acid.