scholarly journals A systematically coarse-grained model for DNA and its predictions for persistence length, stacking, twist, and chirality

2010 ◽  
Vol 132 (3) ◽  
pp. 035105 ◽  
Author(s):  
Alex Morriss-Andrews ◽  
Joerg Rottler ◽  
Steven S. Plotkin
Keyword(s):  
Persistence Length ◽  
Coarse Grained ◽  
Coarse Grained Model

scholarly journals Sequence-dependent Three Interaction Site (TIS) Model for Single and Double-stranded DNA

2018 ◽  
Author(s):  
Debayan Chakraborty ◽  
Naoto Hori ◽  
D. Thirumalai
Keyword(s):  
Electrostatic Interactions ◽  
Persistence Length ◽  
Data Bank ◽  
Coarse Grained ◽  
Force Extension ◽  
Sequence Dependence ◽  
Coarse Grained Model ◽  
Interaction Sites ◽  
Double Stranded Dna ◽  
Centers Of Mass

AbstractWe develop a robust coarse-grained model for single and double stranded DNA by representing each nucleotide by three interaction sites (TIS) located at the centers of mass of sugar, phosphate, and base. The resulting TIS model includes base-stacking, hydrogen bond, and electrostatic interactions as well as bond-stretching and bond angle potentials that account for the polymeric nature of DNA. The choices of force constants for stretching and the bending potentials were guided by a Boltzmann inversion procedure using a large representative set of DNA structures extracted from the Protein Data Bank. Some of the parameters in the stacking interactions were calculated using a learning procedure, which ensured that the experimentally measured melting temperatures of dimers are faithfully reproduced. Without any further adjustments, the calculations based on the TIS model reproduces the experimentally measured salt and sequence dependence of the size of single stranded DNA (ssDNA), as well as the persistence lengths of poly(dA) and poly(dT) chains. Interestingly, upon application of mechanical force the extension of poly(dA) exhibits a plateau, which we trace to the formation of stacked helical domains. In contrast, the force-extension curve (FEC) of poly(dT) is entropic in origin, and could be described by a standard polymer model. We also show that the persistence length of double stranded DNA, formed from two complementary ssDNAs with one hundred and thirty base pairs, is consistent with the prediction based on the worm-like chain. The persistence length, which decreases with increasing salt concentration, is in accord with the Odijk-Skolnick-Fixman theory intended for stiff polyelectrolyte chains near the rod limit. The range of applications, which did not require adjusting any parameter after the initial construction based solely on PDB structures and melting profiles of dimers, attests to the transferability and robustness of the TIS model for ssDNA and dsDNA.

scholarly journals Accurate sequence-dependent coarse-grained model for conformational and elastic properties of double-stranded DNA

2021 ◽  
Author(s):  
Salvatore Assenza ◽  
Rubén Pérez
Keyword(s):  
Persistence Length ◽  
Independent Set ◽  
Single Step ◽  
Coarse Grained ◽  
Atomistic Simulations ◽  
Sequence Dependence ◽  
Cellular Processes ◽  
Coarse Grained Model ◽  
Double Stranded Dna ◽  
Sequence Dependent

AbstractWe introduce MADna, a sequence-dependent coarse-grained model of double-stranded DNA (dsDNA), where each nucleotide is described by three beads localized at the sugar and base moieties, and at the phosphate group. The sequence dependence is included by considering a step-dependent parameterization of the bonded interactions, which are tuned in order to reproduce the values of key observables obtained from exhaustive atomistic simulations from literature. The predictions of the model are benchmarked against an independent set of all-atom simulations, showing that it captures with high fidelity the sequence dependence of conformational and elastic features beyond the single step considered in its formulation. A remarkably good agreement with experiments is found for both sequence-averaged and sequence-dependent conformational and elastic features, including the stretching and torsion moduli, the twist-stretch and twist-bend couplings, the persistence length and the helical pitch. Overall, for the inspected quantities, the model has a precision comparable to atomistic simulations, hence providing a reliable coarse-grained description for the rationalization of singlemolecule experiments and the study of cellular processes involving dsDNA. Owing to the simplicity of its formulation, MADna can be straightforwardly included in common simulation engines.

Insights Into Crowding Effects on Protein Stability From a Coarse-Grained Model

2009 ◽  
Vol 131 (7) ◽  
Author(s):  
Vincent K. Shen ◽  
Jason K. Cheung ◽  
Jeffrey R. Errington ◽  
Thomas M. Truskett
Keyword(s):  
Protein Stability ◽  
Coarse Grained ◽  
Protein Solutions ◽  
Native State ◽  
High Concentration ◽  
Coarse Grained Model ◽  
Excluded Volume Effects ◽  
Thermodynamic Phase ◽  
Broad Interest ◽  
Liquid Liquid Phase Separation

Proteins aggregate and precipitate from high concentration solutions in a wide variety of problems of natural and technological interest. Consequently, there is a broad interest in developing new ways to model the thermodynamic and kinetic aspects of protein stability in these crowded cellular or solution environments. We use a coarse-grained modeling approach to study the effects of different crowding agents on the conformational equilibria of proteins and the thermodynamic phase behavior of their solutions. At low to moderate protein concentrations, we find that crowding species can either stabilize or destabilize the native state, depending on the strength of their attractive interaction with the proteins. At high protein concentrations, crowders tend to stabilize the native state due to excluded volume effects, irrespective of the strength of the crowder-protein attraction. Crowding agents reduce the tendency of protein solutions to undergo a liquid-liquid phase separation driven by strong protein-protein attractions. The aforementioned equilibrium trends represent, to our knowledge, the first simulation predictions for how the properties of crowding species impact the global thermodynamic stability of proteins and their solutions.

scholarly journals Molecular Dynamics Study of Ganglioside GM3/DPPC Membrane by Using Coarse-Grained Model

2016 ◽  
Vol 110 (3) ◽  
pp. 323a
Author(s):  
Kento Inoue ◽  
Eiji Ymamoto ◽  
Daisuke Takaiwa ◽  
Kenji Yasuoka ◽  
Masuhiro Mikami
Keyword(s):  
Molecular Dynamics ◽  
Coarse Grained ◽  
Ganglioside Gm3 ◽  
Coarse Grained Model
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