Folding and unfolding of a giant duplex-DNA in a mixed solution with polycations, polyanions and crowding neutral polymers

Satoru Kidoaki, Kenichi Yoshikawa

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

To understand the conformational behavior of a giant duplex-DNA chain in a mixed solution with various biopolymers with different state of ionization, the higher-order structure of the DNA chain was analyzed with a fluorescence microscope in the presence of polycations (poly-arginine), polyanions (poly-glutamic acid), and neutral polymers (poly-ethylene glycol) as a model for cellular environment. Concentrated medium with neutral polymer induced the discrete folding transition of the DNA. At the threshold condition for the transition, addition of small amounts of either the polycation or the polyanion caused marked structural changes in the folded DNAs. Based on thermodynamic considerations on the experimental results, profile of free energy of a single giant DNA chain was depicted with respect to the size, or the expansion factor α, in the three-dimensional structure of the DNA. The effect of the neural crowding polymer on the degree of folding of a single giant DNA chain is discussed in a semi-quantitative manner. Copyright (C) 1999 Elsevier Science B.V. All rights reserved.

Original languageEnglish
Pages (from-to)133-143
Number of pages11
JournalBiophysical Chemistry
Volume76
Issue number2
DOIs
Publication statusPublished - Feb 1 1999
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Organic Chemistry

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