title: DNA-psoralen interaction: a single molecule experiment.
abstract: By attaching one end of a single lambda-DNA molecule to a microscope coverslip and the other end to a polystyrene microsphere trapped by an optical tweezers, we can study the entropic elasticity of the lambda-DNA by measuring force versus extension as we stretch the molecule. This powerful method permits single molecule studies. We are particularly interested in the effects of the photosensitive drug psoralen on the elasticity of the DNA molecule. We have illuminated the sample with different light sources, studying how the different wavelengths affect the psoralen-DNA linkage. To do this, we measure the persistence length of individual DNA-psoralen complexes.
authors.affiliation: Departamento de Física, ICEX, Universidade Federal de Minas Gerais, Caixa Postal 702, Belo Horizonte, CEP 30123-970 Minas Gerais, Brazil.
authors.forename: M S
authors.initials: MS
authors.lastname: Rocha
authors.forename: N B
authors.initials: NB
authors.lastname: Viana
authors.forename: O N
authors.initials: ON
authors.lastname: Mesquita
mesh_terms: D002627:Chemistry, Physical / Q000379:methods*; D003432:Cross-Linking Reagents / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D018736:DNA Adducts; D019277:Entropy; D005363:Ficusin / Q000737:chemistry*; D007364:Intercalating Agents / Q000737:chemistry; D007700:Kinetics; D008027:Light; D018715:Microscopy, Video / Q000379:methods; D008863:Microspheres; D009690:Nucleic Acid Conformation; D011137:Polystyrenes / Q000737:chemistry; D012542:Scattering, Radiation
chemical_list: D003432:Cross-Linking Reagents; D018736:DNA Adducts; D007364:Intercalating Agents; D011137:Polystyrenes; D004247:DNA; D005363:Ficusin