Stretching weakly bending filaments with spontaneous curvature in two dimensions

Benetatos, Panayotis; Terentjev, Eugene M.

doi:10.1103/physreve.81.031802

Cited by 18 publications

(27 citation statements)

References 24 publications

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“…For the defect to cause a significant shift in the force-extension relation, the deflection length, l f = κ/f , should be of the order of the total contour length or greater. This is expected, as for l f L, the WLC can be viewed as an effective freely jointed chain consisting of links, each of length l f [5]. We point out that the shift in the differential compliance caused by the defect is much more pronounced than the shift in the force-extension relation.…”

Section: Discussion -Conclusionmentioning

confidence: 66%

“…Some important biopolymers, however, exhibit behavior which cannot be accounted for by the simple uniform and isotropic WLC model. One example is the spontaneous curvature in tubulin protofilaments, in bacterial FtsZ or in some cases of eukareotic DNA [4][5][6]. In addition, starting with the pioneering experimental work of Cloutier and Widom, it has become clear that short ds-DNA molecules [7] exhibit highly bendable behavior on short length scales [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Tensile elasticity of semiflexible polymers with hinge defects

Benetatos¹

2017

Phys. Rev. E

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It has become clear in recent years that the simple uniform wormlike chain model needs to be modified in order to account for more complex behavior which has been observed experimentally in some important biopolymers. For example, the large flexibility of short ds-DNA has been attributed to kink or hinge defects. In this paper, we calculate analytically, within the weak bending approximation, the force-extension relation of a wormlike chain with a permanent hinge defect along its contour. The defect is characterized by its bending energy (which can be zero, in the completely flexible case) and its position along the polymer contour. Besides the bending rigidity of the chain, these are the only parameters which describe our model. We show that a hinge defect causes a significant increase in the differential tensile compliance of a pre-stressed chain. In the small force limit, a hinge defect significantly increases the entropic elasticity. Our results apply to any pair of semiflexible segments connected by a hinge. As such, they may also be relevant to cytoskeletal filaments (F-actin, microtubules), where one may treat the cross-link connecting two filaments as a hinge defect.

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Section: Discussion -Conclusionmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Tensile elasticity of semiflexible polymers with hinge defects

Benetatos¹

2017

Phys. Rev. E

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“…6 supports this interpretation. Readers with a background in physics will be interested in two recent papers that examine how protofilaments with an intrinsic curvature are affected by applied bending forces, including the thermal forces acting on a worm-like chain (12,56).…”

Section: Two Different Curved Conformations Of Ftsz Protofilamentsmentioning

confidence: 99%

FtsZ in Bacterial Cytokinesis: Cytoskeleton and Force Generator All in One

Erickson

Anderson

Osawa

2010

Microbiol Mol Biol Rev

557

752

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SUMMARY FtsZ, a bacterial homolog of tubulin, is well established as forming the cytoskeletal framework for the cytokinetic ring. Recent work has shown that purified FtsZ, in the absence of any other division proteins, can assemble Z rings when incorporated inside tubular liposomes. Moreover, these artificial Z rings can generate a constriction force, demonstrating that FtsZ is its own force generator. Here we review light microscope observations of how Z rings assemble in bacteria. Assembly begins with long-pitch helices that condense into the Z ring. Once formed, the Z ring can transition to short-pitch helices that are suggestive of its structure. FtsZ assembles in vitro into short protofilaments that are ∼30 subunits long. We present models for how these protofilaments might be further assembled into the Z ring. We discuss recent experiments on assembly dynamics of FtsZ in vitro, with particular attention to how two regulatory proteins, SulA and MinC, inhibit assembly. Recent efforts to develop antibacterial drugs that target FtsZ are reviewed. Finally, we discuss evidence of how FtsZ generates a constriction force: by protofilament bending into a curved conformation.

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“…Some study has been made of the finite-temperature force response of intrinsically curved polymers, but the problem has only been fully solved in two dimensions [20]. Here we employ a discrete description [21] of a flexible helix, coarse-graining the DNA to the same level as done by the Rigid Base Pair model [22], which we use to numerically assess the force response.…”

Section: (A)mentioning

confidence: 99%

Force responses of strongly intrinsically curved DNA helices deviate from worm-like chain predictions

Tompitak¹,

Schiessel²,

Barkema³

2016

EPL

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DNA sequences with nontrivial intrinsic curvature are of interest for a range of biological and artificial DNA systems. We design both intrinsically strongly curved and intrinsically straight sequences. We find that such sequences with opposing curvatures can be designed even under constraints that would naively lead one to assume that those sequences would be highly similar in their mechanical properties. We then characterize the force response of those sequences and find that their force-extension curves deviate significantly in the low-force regime, and that the standard worm-like chain description is inadequate to describe the low-force response of the strongly bent sequences. We propose a modified description that takes the intrinsic curvature into account, making the DNA act, in the low-force regime, like a nanoscale helical spring. We find strongly improved agreement between the model and the simulated force-extension curves.

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Stretching weakly bending filaments with spontaneous curvature in two dimensions

Cited by 18 publications

References 24 publications

Tensile elasticity of semiflexible polymers with hinge defects

Tensile elasticity of semiflexible polymers with hinge defects

FtsZ in Bacterial Cytokinesis: Cytoskeleton and Force Generator All in One

Force responses of strongly intrinsically curved DNA helices deviate from worm-like chain predictions

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