Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Scaling Concepts in Serpin Polymer Physics.

ABSTRACT: α1-Antitrypsin is a protease inhibitor belonging to the serpin family. Serpin polymerisation is at the core of a class of genetic conformational diseases called serpinopathies. These polymers are known to be unbranched, flexible, and heterogeneous in size with a beads-on-a-string appearance viewed by negative stain electron microscopy. Here, we use atomic force microscopy and time-lapse dynamic light scattering to measure polymer size and shape for wild-type (M) and Glu342→Lys (Z) α1-antitrypsin, the most common variant that leads to severe pathological deficiency. Our data for small polymers deposited onto mica and in solution reveal a power law relation between the polymer size, namely the end-to-end distance or the hydrodynamic radius, and the polymer mass, proportional to the contour length. We use the scaling concepts of polymer physics to assess that α1-antitrypsin polymers are random linear chains with a low persistence length.

SUBMITTER: Raccosta S

PROVIDER: S-EPMC8156723 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Polymer Physics Predicts the Effects of Structural Variants on Chromatin Architecture

Project description:This SuperSeries is composed of the SubSeries listed below.

2018-02-12 | GSE92294 | GEO

Polymer Physics Predicts the Effects of Structural Variants on Chromatin Architecture (mouse)

Project description:Structural variants (SVs) can result in changes in gene expression due to abnormal chromatin folding and consecutive disease. However, the prediction of such effects remains a challenge. Here we present a polymer physics based approach (PRISMR) to model chromatin folding and to predict enhancer-promoter contacts. Using the Epha4 locus as a model, the effects of pathogenic SVs were predicted in-silico and compared to published Hi-C and capture Hi-C data generated from mouse limb buds and patient-derived fibroblasts. PRISMR deconvolutes the folding complexity of the studied locus, and identifies SV-induced alterations of 3D genome organization in the homozygous as well as the heterozygous state. Our method accurately predicts the specific sites of ectopic chromatin contacts that produce extensive rewiring of regulatory interactions, causing disease by gene misexpression. PRISMR can be used to predict interactions in silico thereby providing a tool for analyzing the disease causing potential of SVs.

2018-02-12 | GSE92291 | GEO

Polymer Physics Predicts the Effects of Structural Variants on Chromatin Architecture (human)

2018-02-12 | GSE92290 | GEO

Lithography of Polymer Nanostructures on Glass for Teaching Polymer Chemistry and Physics.

Project description:As nanolithography becomes increasingly important in technology and daily life, a variety of inexpensive and creative methods toward communicating the concepts underpinning these processes in the classroom are necessary. An experiment is described that uses simple CD-Rs, C-clamps, an oven, and a freezer to provide concrete examples and insights into the chemistry and principles of nanolithography. The experiment also has flexibility, making it suitable for a range of classroom levels from high school to more advanced labs in college. Because CD-Rs are composed of grooves of polycarbonate, the experiment provides a basis for discussions and exploration into the chemistry and physics of polymers on the nanoscale.

| S-EPMC3115560 | biostudies-literature

Polymer physics of chromosome large-scale 3D organisation.

Project description:Chromosomes have a complex architecture in the cell nucleus, which serves vital functional purposes, yet its structure and folding mechanisms remain still incompletely understood. Here we show that genome-wide chromatin architecture data, as mapped by Hi-C methods across mammalian cell types and chromosomes, are well described by classical scaling concepts of polymer physics, from the sub-Mb to chromosomal scales. Chromatin is a complex mixture of different regions, folded in the conformational classes predicted by polymer thermodynamics. The contact matrix of the Sox9 locus, a region linked to severe human congenital diseases, is derived with high accuracy in mESCs and its molecular determinants identified by the theory; Sox9 self-assembles hierarchically in higher-order domains, involving abundant many-body contacts. Our approach is also applied to the Bmp7 locus. Finally, the model predictions on the effects of mutations on folding are tested against available data on a deletion in the Xist locus. Our results can help progressing new diagnostic tools for diseases linked to chromatin misfolding.

| S-EPMC4942835 | biostudies-literature

Scaling Laws in Supramolecular Polymer Networks.

Project description:The linear rheological properties of networks formed by adding bis-Pd(II) cross-linkers to poly(4-vinylpyridine) (PVP) solution are examined, and the scaling law relationships between the zero shear viscosity (?(0)) of the networks versus the concentration of PVP solution (C(PVP)), the concentration of cross-linkers (C(X)), and the number density of elastically active chains (v(phantom)) are experimentally determined. The scaling law relationships are compared to the theoretical expectations of the Sticky Rouse and Sticky Reptation models (Macromolecules2001, 34, 1058-1068), and both qualitative and quantitative differences are observed.

| S-EPMC3135979 | biostudies-literature

The biology and polymer physics underlying large-scale chromosome organization.

Project description:Chromosome large-scale organization is a beautiful example of the interplay between physics and biology. DNA molecules are polymers and thus belong to the class of molecules for which physicists have developed models and formulated testable hypotheses to understand their arrangement and dynamic properties in solution, based on the principles of polymer physics. Biologists documented and discovered the biochemical basis for the structure, function and dynamic spatial organization of chromosomes in cells. The underlying principles of chromosome organization have recently been revealed in unprecedented detail using high-resolution chromosome capture technology that can simultaneously detect chromosome contact sites throughout the genome. These independent lines of investigation have now converged on a model in which DNA loops, generated by the loop extrusion mechanism, are the basic organizational and functional units of the chromosome.

| S-EPMC5846894 | biostudies-literature

Models of polymer physics for the architecture of the cell nucleus.

Project description:The depth and complexity of data now available on chromosome 3D architecture, derived by new technologies such as Hi-C, have triggered the development of models based on polymer physics to explain the observed patterns and the underlying molecular folding mechanisms. Here, we give an overview of some of the ideas and models from physics introduced to date, along with their progresses and limitations in the description of experimental data. In particular, we focus on the Strings&Binders and the Loop Extrusion model of chromatin architecture. This article is categorized under: Analytical and Computational Methods > Computational Methods.

| S-EPMC6565494 | biostudies-literature

Two-phase dynamics of DNA supercoiling based on DNA polymer physics.

Project description:DNA supercoils are generated in genome regulation processes such as transcription and replication and provide mechanical feedback to such processes. Under tension, a DNA supercoil can present a coexistence state of plectonemic and stretched phases. Experiments have revealed the dynamic behaviors of plectonemes, e.g., diffusion, nucleation, and hopping. To represent these dynamics with conformational changes, we demonstrated first the fast dynamics on the DNA to reach torque equilibrium within the plectonemic and stretched phases, and then identified the two-phase boundaries as collective slow variables to describe the essential dynamics. According to the timescale separation demonstrated here, we developed a two-phase model on the dynamics of DNA supercoiling, which can capture physiologically relevant events across timescales of several orders of magnitudes. In this model, we systematically characterized the slow dynamics between the two phases and compared the numerical results with those from the DNA polymer physics-based worm-like chain model. The supercoiling dynamics, including the nucleation, diffusion, and hopping of plectonemes, have been well represented and reproduced, using the two-phase dynamic model, at trivial computational costs. Our current developments, therefore, can be implemented to explore multiscale physical mechanisms of the DNA supercoiling-dependent physiological processes.

| S-EPMC8873955 | biostudies-literature