Nielsen P E, Møllegaard N E, Jeppesen C
Department of Biochemistry B, Panum Institute, University of Copenhagen, Denmark.
Nucleic Acids Res. 1990 Jul 11;18(13):3847-51. doi: 10.1093/nar/18.13.3847.
Uranyl mediated photocleavage of double stranded DNA is proposed as a general probing for DNA helix conformation in terms of minor groove width/electronegative potential. Specifically, it is found that A/T-tracts known to constitute strong distamycin binding sites are preferentially photocleaved by uranyl in a way indicating strongest uranyl binding at the center of the minor groove of the AT-region. The A-tracts of kinetoplast DNA show the highest reactivity at the 3'-end of the tract--as opposed to cleavage by EDTA/Fell--in accordance with the minor groove being more narrow at this end. Finally, uranyl photocleavage of the internal control region (ICR) of the 5S-RNA gene yields a cleavage modulation pattern fully compatible with that obtained by DNase I which also--in a more complex way--senses DNA minor groove width.
基于小沟宽度/负电电势，提出了铀酰介导的双链DNA光裂解作为DNA螺旋构象的一种通用探测方法。具体而言，发现已知构成强力偏端霉素结合位点的A/T序列优先被铀酰光裂解，其方式表明在AT区域小沟中心铀酰结合最强。动质体DNA的A序列在序列的3'端显示出最高反应性——这与EDTA/FeII介导的裂解相反——这与该末端小沟更窄一致。最后，5S - RNA基因内部控制区（ICR）的铀酰光裂解产生的裂解调节模式与DNase I获得的模式完全兼容，DNase I也是以一种更复杂的方式感知DNA小沟宽度。
