title: Effects of DNA looping on pyrimidine dimer formation.
abstract: We have assessed the effects of DNA curvature on pyrimidine dimer (PD) formation by examining the pattern of PD formation in DNA held in a loop by lambda repressor. The loop region was composed of diverse DNA sequences such that potential PD sites occurred throughout the loop. PD formation in the loop occurred with peaks at approximately 10 base intervals, just 3' of where the bending of the DNA was inferred to be toward the major groove. This relationship between the peaks and the DNA curvature is essentially identical to that observed in the nucleosome. This indicates that DNA curvature is the major source of the periodicity of PD formation in the nucleosome, and supports an earlier model of the conformation of nucleosomal DNA based on PD formation. DNA loops containing diverse sequences should be of general value for assessing the effects of DNA curvature on DNA modification by other agents used to probe DNA-protein interactions and DNA conformation.
authors.affiliation: Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111.
authors.forename: J R
authors.initials: JR
authors.lastname: Pehrson
authors.forename: L H
authors.initials: LH
authors.lastname: Cohen
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000528:radiation effects; D004268:DNA-Binding Proteins; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011740:Pyrimidine Dimers / Q000737:chemistry*; D012097:Repressor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D004268:DNA-Binding Proteins; D011740:Pyrimidine Dimers; D012097:Repressor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D004247:DNA