DNA H-FORM REQUIRES A HOMOPURINE HOMOPYRIMIDINE MIRROR REPEAT
DNA H-FORM REQUIRES A HOMOPURINE HOMOPYRIMIDINE MIRROR REPEAT
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DOI：
10.1038/330495a0
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发表时间：
1987-12-03
期刊：
影响因子：
64.8
通讯作者：
FRANKKAMENETSKII, MD
中科院分区：
文献类型：
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作者：
MIRKIN, SM;LYAMICHEV, VI;FRANKKAMENETSKII, MD
规则的同型嘌呤-同型嘧啶片段（dG-dA）n·（dT-dC）n（dG）R·（dC）n），通过超螺旋诱导的强pH依赖性结构转变为一种新的DNA构象，即H型1 -3。我们认为H型可以出现在任何同型嘌呤-同型嘧啶镜像重复序列（H回文）3中。我们现在已经用一系列带有插入片段AAGGG AG AAXGGGGTATAGGGGYAAG AGGGAA（其中X和Y可以是A或G）的定制质粒测试了这一预测，并将它们进行二维凝胶电泳。为了支持我们的假设，插入物表现出容易的过渡到H形式的X = Y = G，或X = Y = A，而过渡是更困难或不可能的两个非回文（X = A，Y = G或X = G，Y = A）。我们提出的证据表明，H型是SL-核酸酶超敏反应的结构基础。
Regular homopurine-homopyrimidine tracts, (dG–dA)n·(dT–dC)nand (dG)R·(dC)n, undergo a superhelix-induced, stronglypH-dependent, structural transition into a novel DNA conformation, the H form1–3. We have suggested that the H form can arise in any homopurine-homopyrimidine mirror repeat (H palindrome)3. We have now tested this prediction using a tailored series of plasmids carrying the inserts AAGGG AG AAXGGGGTATAGGGGYAAG AGGGAA, where X and Y may be either A or G, and subject them to two-dimensional gel electrophoresis. In support of our hypothesis, the inserts exhibited facile transitions into the H form for X = Y = G, or X = Y = A, whereas the transition was much more difficult or impossible for the two non-palindromes (X = A, Y = G or X = G, Y = A). We present evidence that the H form is the structural basis for Sl-nuclease hypersensitivity.