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Protein molecules can be approximated by discrete polygonal chains of amino acids. Standard topological tools can be applied to the smoothening of the polygons to introduce a topological classification of proteins, for example, using the…

Biomolecules · Quantitative Biology 2019-03-12 Dmitry Melnikov , Antti J Niemi , Ara Sedrakyan

Protein structures in nature often exhibit a high degree of regularity (secondary structures, tertiary symmetries, etc.) absent in random compact conformations. We demonstrate in a simple lattice model of protein folding that structural…

Condensed Matter · Physics 2009-10-28 Hao Li , Robert Helling , Chao Tang , Ned Wingreen

We have shown recently that the notion of poking pairwise interactions along a chain provides a unifying framework for understanding the formation of both secondary and the tertiary protein structure based on symmetry and geometry.…

Soft Condensed Matter · Physics 2023-12-13 Tatjana Škrbić , Achille Giacometti , Trinh X. Hoang , Amos Maritan , Jayanth R. Banavar

Quantification and classification of protein structures, such as knotted proteins, often requires noise-free and complete data. Here we develop a mathematical pipeline that systematically analyzes protein structures. We showcase this…

Most biological processes are described as a series of interactions between proteins and other molecules, and interactions are in turn described in terms of atomic structures. To annotate protein functions as sets of interaction states at…

Biomolecules · Quantitative Biology 2012-02-13 Akira R. Kinjo , Haruki Nakamura

Although rare, an increasing number of proteins have been observed to contain entanglements in their native structures. To gain more insight into the significance of protein knotting, researchers have been investigating protein knot…

Biomolecules · Quantitative Biology 2022-11-08 Isabel K. Darcy , Garrett Jones , Puttipong Pongtanapaisan

We propose that protein loops can be interpreted as topological domain-wall solitons. They interpolate between ground states that are the secondary structures like alpha-helices and beta-strands. Entire proteins can then be folded simply by…

Biological Physics · Physics 2014-11-20 M. N. Chernodub , Shuangwei Hu , Antti J. Niemi

Molecular dynamics studies within a coarse-grained structure based model were used on two similar proteins belonging to the transcarbamylase family to probe the effects in the native structure of a knot. The first protein, N-acetylornithine…

Biomolecules · Quantitative Biology 2009-02-17 Joanna I. Sułkowska , Piotr Sułkowski , P. Szymczak , Marek Cieplak

Proteins, by virtue of their central role in most biological processes, represent one of the key subjects of the study of molecular evolution. Inherent to the indispensability of proteins for living cells is the fact that a given protein…

Biomolecules · Quantitative Biology 2007-05-23 Eric J. Deeds , Eugene I. Shakhnovich

Many types of peripheral and transmembrane proteins can sense and generate membrane curvature. Laterally isotropic proteins and crescent proteins with twofold rotational symmetry, such as Bin/Amphiphysin/Rvs superfamily proteins, have been…

Soft Condensed Matter · Physics 2024-02-12 Hiroshi Noguchi

Cooperativity is a hallmark of proteins, many of which show a modular architecture comprising discrete structural domains. Detecting and describing dynamic couplings between structural regions is difficult in view of the many-body nature of…

Biological Physics · Physics 2015-02-03 Olga Kononova , Lee Jones , Valeri Barsegov

The topological framework of circuit topology has recently been introduced to complement knot theory and to help in understanding the physics of molecular folding. Naturally evolved linear molecular chains, such as proteins and nucleic…

Geometric Topology · Mathematics 2021-09-07 Alireza Mashaghi , Roland van der Veen

We study theta-curves embedded in a standard torus in the 3-sphere. We show that each nontrivial torus knot together with an essential arc determines a prime theta-curve, yielding explicit infinite families of prime theta-curves. We compute…

Geometric Topology · Mathematics 2026-04-01 Jack S. Calcut , Samantha E. Nieman

Proteins can sometimes be knotted, and for many reasons the study of knotted proteins is rapidly becoming very important. For example, it has been proposed that a knot increases the stability of a protein. Knots may also alter enzymatic…

Soft Condensed Matter · Physics 2009-07-02 Martin Lundgren , Antti J. Niemi

These lectures will address two questions. Is there a simple variational principle underlying the existence of secondary motifs in the native state of proteins? Is there a general approach which can qualitatively capture the salient…

Statistical Mechanics · Physics 2007-05-23 Jay Banavar , Amos Maritan , Cristian Micheletti , Flavio Seno

A framework is presented for understanding the common character of proteins. Proteins are linear chain molecules. However, the simple model of a polymer viewed as spheres tethered together does not account for many of the observed…

Statistical Mechanics · Physics 2009-11-10 Jayanth R. Banavar , Amos Maritan

We present a systematic classification of uncolored bonded knots with singularity number at most seven. Bonded knots provide a topological model for closed protein chains with intramolecular bridges, such as disulfide bonds. Following the…

Geometric Topology · Mathematics 2026-03-20 Boštjan Gabrovšek , Matic Simonič , Wanda Niemyska

Focusing on a small set of proteins that i) fold in a concerted, all-or-none fashion and ii) do not contain knots or slipknots, we show that the Gauss linking integral, the torsion and the number of sequence-distant contacts provide…

Quantitative Methods · Quantitative Biology 2019-10-01 E. Panagiotou , K. W. Plaxco

Approximately 1% of the known protein structures display knotted configurations in their native fold but their function is not understood. It has been speculated that the entanglement may inhibit mechanical protein unfolding or transport,…

Biological Physics · Physics 2009-11-13 Joachim Dzubiella

Proteins must fold quickly to acquire their biologically functional three-dimensional native structures. Hence, these are mainly stabilized by local contacts, while intricate topologies such as knots are rare. Here, we reveal the existence…

Biomolecules · Quantitative Biology 2019-06-20 Marco Baiesi , Enzo Orlandini , Flavio Seno , Antonio Trovato