title: Condensation of DNA-actin polyelectrolyte mixtures driven by ions of different valences.
abstract: Multivalent ions can induce condensation of like-charged polyelectrolytes into compact states, a process that requires different ion valences for different polyelectrolyte species. In this work we examine the condensation behavior in binary anionic polyelectrolyte mixtures consisting of DNA coils and F-actin rods in the presence of monovalent, divalent, and trivalent ions. As expected, monovalent ions do not condense either component and divalent ions selectively condense F-actin rods out of the polyelectrolyte mixture. For trivalent ions, however, we observe a microphase separation between the two polyelectrolytes into coexisting finite-sized F-actin bundles and DNA toroids. Further, by increasing the DNA volume fraction in the mixture, condensed F-actin bundles can be completely destabilized, leading to only DNA condensation within the mixture. We examine a number of possible causes and propose a model based on polyelectrolyte competition for ions.
authors.affiliation: Department of Materials Science & Engineering, University of Illinois at Urbana-Champaign, Illinois 61801, USA.
authors.forename: Olena V
authors.initials: OV
authors.lastname: Zribi
authors.forename: Hee
authors.initials: H
authors.lastname: Kyung
authors.forename: Ramin
authors.initials: R
authors.lastname: Golestanian
authors.forename: Tanniemola B
authors.initials: TB
authors.lastname: Liverpool
authors.forename: Gerard C L
authors.initials: GC
authors.lastname: Wong
mesh_terms: D000199:Actins / Q000737:chemistry*; D011232:Chemical Precipitation; D045424:Complex Mixtures / Q000737:chemistry; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods; D004247:DNA / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry*; D007477:Ions; D008956:Models, Chemical; D044367:Phase Transition; D055672:Static Electricity
chemical_list: D000199:Actins; D045424:Complex Mixtures; D004573:Electrolytes; D007477:Ions; D004247:DNA