title: Centromere parC of plasmid R1 is curved.
abstract: 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.
authors.affiliation: Institute for Molecular Biotechnology e.V., Beutenbergstr. 11, D-07745 Jena, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Hoischen
authors.forename: Alexander
authors.initials: A
authors.lastname: Bolshoy
authors.forename: Kenn
authors.initials: K
authors.lastname: Gerdes
authors.forename: Stephan
authors.initials: S
authors.lastname: Diekmann
mesh_terms: D001483:Base Sequence; D002503:Centromere / Q000737:chemistry*; D004269:DNA, Bacterial / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000737:chemistry*
chemical_list: D004269:DNA, Bacterial