title: Low-force DNA condensation and discontinuous high-force decondensation reveal a loop-stabilizing function of the protein Fis.
abstract: We report single-DNA-stretching experiments showing that the protein Fis, an abundant bacterial chromosome protein of E. coli, mediates a dramatic DNA condensation to zero length. This condensation occurs abruptly when DNA tension is reduced below a protein-concentration-dependent threshold f* < 1 pN. Following condensation, reopening under larger forces proceeds via a series of discrete jumps, indicating that Fis is able to stabilize DNA crossings. Our experiments suggest that Fis may play a role in vivo stabilizing the "loop-domain" structure of the bacterial chromosome.
authors.affiliation: Department of Physics, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7059, USA.
authors.forename: Dunja
authors.initials: D
authors.lastname: Skoko
authors.forename: Jie
authors.initials: J
authors.lastname: Yan
authors.forename: Reid C
authors.initials: RC
authors.lastname: Johnson
authors.forename: John F
authors.initials: JF
authors.lastname: Marko
mesh_terms: D004269:DNA, Bacterial / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D035021:Factor For Inversion Stimulation Protein; D033081:Shear Strength; D014157:Transcription Factors / Q000737:chemistry*
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; C501034:Fis protein, E coli; D014157:Transcription Factors