title: DNA condensation induced by a cationic polymer studied by atomic force microscopy and electrophoresis assay.
abstract: We synthesized a cationic polymer, poly(PEGMA)-4N, which has brush-like chains and four positively charged amino groups at the end of the molecules. DNA condensation induced by poly(PEGMA)-4N was investigated through electrophoresis assay by its ability to retard DNA mobility and to inhibit HindIII enzyme cleavage. The detailed structures of DNA condensates induced by poly(PEGMA)-4N were observed through atomic force microscopy (AFM). Interactions between polymers and DNA are mainly attributed into depletion effect and electrostatic interaction. Positively charged amino groups in poly(PEGMA)-4N interact with DNA through electrostatic interaction, and depletion effect also takes effect because poly(PEGMA)-4N is a flexible polymer. Comparing the contributions that the two interactions gave in DNA condensation process, we found that depletion effect played a major role compared with electrostatic interaction.
authors.affiliation: College of Life Science, Nankai University, Tianjin, PR China.
authors.forename: Sen
authors.initials: S
authors.lastname: Hou
authors.forename: Kun
authors.initials: K
authors.lastname: Yang
authors.forename: Yang
authors.initials: Y
authors.lastname: Yao
authors.forename: Ze
authors.initials: Z
authors.lastname: Liu
authors.forename: Xizeng
authors.initials: X
authors.lastname: Feng
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Yanlian
authors.initials: Y
authors.lastname: Yang
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
mesh_terms: D004247:DNA / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel; D008689:Methacrylates; D018625:Microscopy, Atomic Force; D011092:Polyethylene Glycols
chemical_list: D008689:Methacrylates; C531046:poly(PEGMA)-4N; D011092:Polyethylene Glycols; D004247:DNA