Preferential location of bulged guanosine internal to a G.C tract by 1H NMR.
Preferential location of bulged guanosine internal to a G.C tract by 1H NMR.
复制标题
通过 1H NMR 确定 G.C 区域内凸出的鸟苷的优先位置。
DOI：
10.1021/bi00401a065
复制
发表时间：
1988
期刊：
影响因子：
2.9
通讯作者：
Crothers,DM
中科院分区：
文献类型：
--
作者：
Woodson,SA;Crothers,DM
莎拉·A Woodson和Donald M. Crothers* Department of Chemistry，Yale University，New Haven，Connecticut 06511 Received June 25，1987; Revised Mandarin pt Received September 10，1987摘要：通过质子磁共振波谱在500 MHz的可交换质子下比较了一系列序列对应于CT基因中的移码突变热点5 '-dGATGGGGCAG的双螺旋寡脱氧核糖核苷酸。将在两个、三个和四个GC碱基对的运行中含有额外鸟嘌呤的双链体与相同序列的规则螺旋和含有分离的凸出G，S ′-dGATGGGCAG-dCTGCGCCATC的另一个序列进行比较。亚氨基质子共振由一维核Overhauser效应谱指定。在含有凸起的双链体中，归属于G束的共振被错误地移向高场，并且非常宽。亚胺质子寿命由T1反转-恢复实验确定。交换率的G-道亚氨基质子在凸出的双链体是快速comparedto那些在规则的螺旋，并讨论了孤立的G凸起的溶剂交换的表观速率。在均聚物序列中的凸起鸟苷的离域可以解释在整个GC运行中化学位移和弛豫时间的快速变化，并且化学位移可以通过亚氨基质子的碱基配对和未配对状态之间的快速交换的简单模型来拟合。这使我们能够计算每个凸起部位的相对占有率。在这些序列中，我们发现额外的碱基更喜欢G道内部的位置，而不是边缘的位置。
Sarah A. Woodson and Donald M. Crothers* Department of Chemistry, Yale University, New Haven, Connecticut 06511 Received June 25, 1987; Revised Manuscript Received September 10, 1987 abstract: A series of double-helical oligodeoxyribonucleotides of sequence corresponding to a frame-shift mutational hotspot in the CT gene, 5'-dGATGGGGCAG, are compared by proton magnetic resonance spectroscopy at 500 MHz of the exchangeable protons. Duplexes containing an extra guanine in a run of two, three, and four GC base pairs are compared to regular helices of the same sequence and to another sequence containing an isolated bulged G, S'-dGATGGGCAG-dCTGCGCCATC. The imino proton resonances are assigned by one-dimensional nuclear Overhauser effect spectroscopy. Resonances assigned to theG tract in bulge-containing duplexes are shifted anomalously upfield and are very broad. Imino proton lifetimes are determined by T\inversion-recovery experiments. The exchange rates of G-tract imino protons in bulged duplexes are rapid comparedto those in regular helices and are discussed in terms of the apparent rate of solvent exchange for the isolated G bulge. Delocalization of a bulged guanosine in homopolymeric sequences can explain the observedchanges in chemical shift and relaxation times across the entire GC run, and the chemical shifts can be fit by a simple model of fast exchange between base-paired and unpaired states for the imino protons. This allows us to calculate the relative occupancies of each bulge site. In these sequences, we find the extra base prefers positions internal to the G tract over those at the edge.