title: Long-time stretched exponential kinetics in single DNA duplex dissociation.
abstract: We probe DNA hybridization kinetics by measuring the lifetime distribution of single 16-bp duplexes under thermal dissociation. Our unique approach, based on two DNA-coated microspheres in an extended optical tweezer, allows the study of single duplex DNA molecules under negligible molecular tension. In contrast to earlier experiments, we find a stretched exponential lifetime distribution, which is likely due to dissociation proceeding via a number of competing pathways between highly force-sensitive intermediate states. Similar measurements of microspheres linked by multiple DNA bridges find they have unexpected short bound lifetimes, also consistent with force sensitivity.
authors.affiliation: Department of Physics and Astronomy, The University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Biancaniello
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Kim
authors.forename: John C
authors.initials: JC
authors.lastname: Crocker
mesh_terms: D003198:Computer Simulation; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D004548:Elasticity; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D052898:Optical Tweezers; D013314:Stress, Mechanical
chemical_list: D004247:DNA