Uranyl photofootprinting.
The uranyl-(VI) cation (UO(2) (2+)) forms strong complexes with accessible phosphates of nucleic acid (DNA and RNA) backbones. Upon excitation with long wavelength ultraviolet light (lambda = 300-420 nm), uranyl ions bound to backbone phosphates oxidize proximal sugars and induce nucleic acid backbone cleavage. Thus the uranyl(VI) ion functions as a very specific and efficient photochemical probe for identifying ligand(protein)-phosphate contacts in nucleic acid complexes as well as potential (high affinity) cation (e.g., Mg(2+))-binding sites in folded nucleic acids. Finally, the cleavage modulation of duplex DNA reflects helix conformation in terms of minor groove width, due to preferential affinity/oxidation efficiency for such regions of the DNA helix.
Nielsen
Peter E
PE
Department of Cellular and Molecular Medicine, University of Copenhagen, The Panum Institute, Blegdamsvej 3c, 2200 Copenhagen N, Denmark.
D000818:Animals; D001483:Base Sequence; D002417:Cattle; D018983:DNA Footprinting / Q000379:methods*; D003850:Deoxyribonuclease I / Q000378:metabolism; D008027:Light; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D012097:Repressor Proteins / Q000378:metabolism; D017974:Uranium Compounds / Q000737:chemistry*; D054334:Viral Regulatory and Accessory Proteins / Q000378:metabolism
D012097:Repressor Proteins; D017974:Uranium Compounds; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D003850:Deoxyribonuclease I