Unbundling and desorption of semiflexible polymers

Abstract

A complete classification for unbundling transitions of two semiflexible polymers and for desorption transitions of such polymers at planar surfaces is presented. The interaction potentials can depend both on the polymer/polymer (or polymer/surface) separation and on the orientation of the polymers. Using analytical transfer matrix methods and scaling arguments, the order of the transitions and the corresponding critical exponents are obtained for all types of interaction potentials in arbitrary spatial dimension d = 1 + d ⊥. Our results are applicable to biopolymers or polyelectrolytes with large persistence lengths such as actin filaments, microtubules, or DNA. c EDP Sciences (1)The exponent χ was previously denoted by x or by ζ 2 and governs the contact probability which scales as 1/ξ χ with the longitudinal correlation length ξ .

Adhesion-Induced DNA Naturation

“…When the two strands are tightly connected to each other, the double strand is described via a single semiflexible chain [5][6][7]. Indeed, for the double-stranded DNA the corresponding persistence length l p is about 100 nm [8], or 300 base pairs.…”

“…A realistic model of DNA should include stacking energy between two base pairs, the helical structure, self-avoidance, heterogeneity, etc. Such models do not seem to exist; there are, however, various models with different degrees of sophistication capturing at least some aspects of the problem [2,[5][6][7][10][11][12].…”

A wormlike chain model of forced desorption of a polymer adsorbed on an attractive wall

“…The theoretical analyses of the desorption of polymer have been carried out using models such as freely jointed chain (FJC) or wormlike chain model (WLC) [18][19][20]. In WLC, the persistence length is introduced.…”

Nanoscale dynamics and aging of fibrous peptide-based gels

“…[6][7][8][9][10][11][12][13][14] To do so, extant theories (and many simulations as well) have appealed to approximations that are not generally justified by the underlying chemical kinetics. For example, it is commonly assumed that nonequilibrium considerations are important only for the discrete, driven part of the ratcheting process; all other degrees of freedom are imagined to follow adiabatically.…”

“…In this approximation, the fluctuating obstacle is replaced by an effective, steady force acting directly on the discrete elements of the ratchet. This assumption of rapid equilibration is explicit in some stochastic models of polymerization ratchets, [6][7][8][9][10] implicit in some phenomenological models of actin gels, 11,12 and inherent to continuum models of growing gels. 13,14 While this effective-force approximation can be justified on thermoa) Electronic mail: evanhohlfeld@gmail.com b) Electronic mail: geissler@berkeley.edu dynamic grounds when external loads are sufficiently strong to stall the ratchet, 8 most biological ratchets operate far from stall conditions.…”