Guglielmi L, Gianfranceschi G L, Venanzi F, Polzonetti A, Amici D
Mol Biol Rep. 1979 Feb 15;4(4):195-201. doi: 10.1007/BF00777553.
Low molecular weight peptides from calf thymus cause a strong dose-dependent stabilization of the DNA. The strength od DNA-peptide interaction is pH-dependent and decreases repidly above pH 6.5. Moreover the complete kinetics of DNA denaturation and renaturation demonstrates that the peptide fraction increases significantly the DNA renaturation mostly at low temperature, showing that the interaction DNA-thymic effector helps the recombination of complementary DNA segments. The DNA stabilization rate by the peptide fraction is comparable to that obtained by means of high concentration of histones or synthetic polycationic peptides. However, the lack of basic amino acids in the peptide structure is not in favor of strong electrostatic interactions and implies a specific binding of peptide to DNA. The possible correlation of the specific thymic peptides-DNA interaction with the stereochemical kinking scheme of DNA is discussed.
来自小牛胸腺的低分子量肽可引起DNA强烈的剂量依赖性稳定。DNA-肽相互作用的强度依赖于pH值，在pH 6.5以上迅速降低。此外，DNA变性和复性的完整动力学表明，肽组分主要在低温下显著增加DNA复性，表明DNA-胸腺效应物的相互作用有助于互补DNA片段的重组。肽组分对DNA的稳定率与通过高浓度组蛋白或合成聚阳离子肽获得的稳定率相当。然而，肽结构中缺乏碱性氨基酸不利于强静电相互作用，这意味着肽与DNA存在特异性结合。本文讨论了特定胸腺肽与DNA相互作用与DNA立体化学扭结模式之间可能的相关性。
