title: Local de-condensation of double-stranded DNA in oppositely charged polyelectrolyte as induced by spermidine.
abstract: How polyamines such as spermidine cooperate with histone to condense and de-condense DNA during transcription has not been clarified. In this work, using the complex of DNA and poly(L-lysine) (PLL) at +/- ratio of 0.5 as a model of nucleosome, we monitored the de-condensation of DNA in the presence of spermidine. As revealed by the results from atomic force microscopy and time-resolved laser light scattering, spermidine was able to transform the spherical complex into a core-shelled structure, with the hard core being the DNA-PLL complex and the soft shell being DNA and spermidine. The soft shell evolved into a coiled DNA conformation with time. Such a local de-condensation process should be helpful in understanding the DNA transcription and cell division process in vivo.
authors.affiliation: Beijing National Laboratory for Molecular Sciences and the Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China. dliang@pku.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
authors.forename: Jihan
authors.initials: J
authors.lastname: Zhou
authors.forename: Yudan
authors.initials: Y
authors.lastname: Yin
authors.forename: Hao
authors.initials: H
authors.lastname: Wen
authors.forename: Dehai
authors.initials: D
authors.lastname: Liang
mesh_terms: D004247:DNA / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D009690:Nucleic Acid Conformation; D011107:Polylysine / Q000737:chemistry*; D013095:Spermidine / Q000737:chemistry*
chemical_list: D011107:Polylysine; D004247:DNA; D013095:Spermidine