Hoischen Christian, Bolshoy Alexander, Gerdes Kenn, Diekmann Stephan
Institute for Molecular Biotechnology e.V., Beutenbergstr. 11, D-07745 Jena, Germany.
Nucleic Acids Res. 2004 Nov 4;32(19):5907-15. doi: 10.1093/nar/gkh920. Print 2004.
The centromere sequence parC of Escherichia coli low-copy-number plasmid R1 consists of two sets of 11 bp iterated sequences. Here we analysed the intrinsic sequence-directed curvature of parC by its migration anomaly in polyacrylamide gels. The 159 bp long parC is strongly curved with anomaly values (k-factors) close to 2. The properties of the parC curvature agree with those of other curved DNA sequences. parC contains two regions of 5-fold repeated iterons separated by 39 bp. We modified 4 bp within this intermediate sequence so that we could analyse the two 5-fold repeated regions independently. The analysis shows that the two repeat regions are not independently curved parts of parC but that the overall curvature is a property of the whole fragment. Since the centromere sequence of an E.coli plasmid as well as eukaryotic centromere sequences show DNA curvature, we speculate that curvature might be a general property of centromeres.
大肠杆菌低拷贝数质粒R1的着丝粒序列parC由两组11 bp的重复序列组成。在此，我们通过聚丙烯酰胺凝胶中的迁移异常分析了parC的内在序列导向曲率。159 bp长的parC具有强烈的弯曲，异常值（k因子）接近2。parC曲率的特性与其他弯曲DNA序列的特性一致。parC包含两个由39 bp隔开的5倍重复迭代子区域。我们在这个中间序列中修饰了4 bp，以便能够独立分析这两个5倍重复区域。分析表明，这两个重复区域不是parC独立的弯曲部分，而是整个片段的整体曲率特性。由于大肠杆菌质粒的着丝粒序列以及真核生物着丝粒序列都显示出DNA曲率，我们推测曲率可能是着丝粒的一个普遍特性。
