小肽对Hoechst33258与DNA特异部位结合的竞争性作用

为了了解小肽如何识别ＤＮＡ特异的结合位点，我们研究了两个小肽ＹＲ和ＧＧＨ对ＤＮＡ与Ｈｏｅｃｈｓｔ３３２５８特异结合的竞争性抑制作用。对Ｌｉｎｅｗｅａｖｅｒ－Ｂｕｒｋ图的分析显示当Ｈｏｅｃｈｓｔ３３２５８的浓度在３．６６（１０－９ｍｏｌ／Ｌ（１．０９（１０－８ｍｏｌ／Ｌ范围内，这种作用是典型的竞争性抑制作用，ＹＲ结合在ＤＮＡ小沟区（ＡＴ富集区），结合常数为１．０２（１０８（ｍｏｌ／Ｌ）－１，而ＧＧＨ的ＡＴ富集区结合特异性在浓度高时明显减弱，因为它也能与ＧＣ碱基结合

Studies of Site Specific DNA Binding of Small Peptides by Competitive Assays with Hoechst 33258

With a view to finding out precisely how small peptides recognize a particular binding site of DNA, we have accomplished DNA binding studies of two peptides, H-Tyr-Arg-OH (YR) and H-Gly-Gly-His-OH (GGH) by using measurements in comparison with the binding between DNA and Hoechst 33258. The inhibition mode by YR and GGH to DNA binding of Hoechst 33258 was analyzed by Lineweaver-Burk plot which shows the plot of typical competitive inhibition at concentration of Hoechst 33258 from 3.66 ( 10-9 mol / L to 1.09 ( 10-8 mol / L. And it is concluded that YR binds to DNA in its minor groove (AT rich regions) with a binding constant K = 1.02 ( 108 (mol / L)-1. The GGH(s specificity is reduced at high concentration because it can also bind GC base pair.