title: First-order phase transition in large single duplex DNA induced by a nonionic surfactant.
abstract: The effect of the nonionic surfactant Triton X-100 on the conformational behavior of large T4DNA was studied. Through single-molecule observation using fluorescence microscopy, we found that T4DNA macromolecules exhibit a discrete coil-globule transition with an increase in the Triton X-100 concentration. At low surfactant concentrations, all of the DNAs exhibited an elongated coil state, whereas only compacted globular DNAs were observed at high molar fractions of Triton X-100. The formation of DNA globules was not detected at relatively low Triton X-100 concentrations, even above the CMC; DNA collapse occurred in 50-90% solutions of Triton X-100. The increase in osmotic pressure in concentrated Triton X-100 solutions is considered to be the driving force for the compaction of single T4DNAs.
authors.affiliation: Graduate School of Human Informatics, Nagoya University, Japan.
authors.forename: S M
authors.initials: SM
authors.lastname: Mel'nikov
authors.forename: K
authors.initials: K
authors.lastname: Yoshikawa
mesh_terms: D017122:Bacteriophage T4 / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D004277:DNA, Single-Stranded / Q000187:drug effects / Q000502:physiology*; D004279:DNA, Viral / Q000187:drug effects / Q000502:physiology*; D008856:Microscopy, Fluorescence; D009690:Nucleic Acid Conformation / Q000187:drug effects*; D017830:Octoxynol / Q000494:pharmacology*
chemical_list: D004277:DNA, Single-Stranded; D004279:DNA, Viral; D017830:Octoxynol