Force field parameters for the simulation of modified histone tails (original) (raw)
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Biopolymers, 2014
The positively charged N-terminal histone tails play a crucial role in chromatin compaction and are important modulators of DNA transcription, recombination, and repair. The detailed mechanism of the interaction of histone tails with DNA remains elusive. To model the unspecific interaction of histone tails with DNA, all-atom molecular dynamics (MD) simulations were carried out for systems of four DNA 22-mers in the presence of 20 or 16 short fragments of the H4 histone tail (variations of the 16-23 a. a. KRHRKVLR sequence, as well as the unmodified fragment a. a.13-20, GGAKRHRK). This setup with high DNA concentration, explicit presence of DNA-DNA contacts, presence of unstructured cationic peptides (histone tails) and K 1 mimics the conditions of eukaryotic chromatin. A detailed account of the DNA interactions with the histone tail fragments, K 1 and water is presented. Furthermore, DNA structure and dynamics and its interplay with the histone tail fragments binding are analysed. The charged side chains of the lysines and arginines play major roles in the tailmediated DNA-DNA attraction by forming bridges and by coordinating to the phosphate groups and to the electronegative sites in the minor groove. Binding of all species to DNA is dynamic. The structure of the unmodified fully-charged H4 16-23 a.a. fragment KRHRKVLR is dominated by a stretched conformation. The H4 tail a. a. fragment GGAKRHRK as well as the H4 Lys16 acetylated fragment are highly flexible. The present work allows capturing typical features of the histone tail-counterion-DNA structure, interaction and dynamics. V
Modeling H3 histone N-terminal tail and linker DNA interactions
Biopolymers, 2006
Molecular dynamics computer simulations were performed for the 25-residue N-terminal tail of the H3 histone protein in the proximity of a DNA segment of 10 base pairs (bp), representing a model for the linker DNA in chromatin. Several least biased configurations were used as initial configurations. The secondary structure content of the protein was increased by the presence of DNA close to it, but the locations of the secondary motifs were different for different initial orientations of the DNA grooves with respect to the protein. As a common feature to all simulations, the electrostatic attraction between negatively charged DNA and positively charged protein was screened by the water solvent and counterbalanced by the intrinsic compaction of the protein due to hydrophobic effects. The protein secondary structure limited the covering of DNA by the protein to 4-5 bp. The degree of compaction and charge density of the bound protein suggests a possible role of H3 tail in a nonspecific bending and plasticity of the linker DNA when the protein is located in the crowded dense chromatin. #
ScienceDirect, 2021
The atomic interactions between histone molecule and 3LPT protein are reported using the molecular dynamics (MD) method in this computational work. This computational study is done for the first time. The results of the MD simulations on the dynamical manner of these structures have been reported by calculating various physical parameters. Physically, our results show that the attraction forces between the histone molecule and 3LPT protein destructed the 3LPT protein after 2 ns. Further, the temperature and pressure of these structures are important parameters in their atomic interactions. Numerically, by increasing these two parameters from 300 K to 350 K and 0 to 1 bar, respectively, the interatomic distance between these structures decreases from 7 Å to 2.54 Å and 7 Å to 2.79 Å (respectively). Further, bonding energy in these simulations varies from 23.51 eV to 31.78 eV. The diffusion coefficient of histone structure into 3LPT protein is another important parameter. Numerically , this physical coefficient changes from 0.58μm 2 /s to 0.89 μm 2 /s.
An all atom force field for simulations of proteins and nucleic acids
Journal of …, 1986
We present an all atom potential energy function for the simulation of proteins and nucleic acids. This work is an extension of the CH united atom function recently presented by S. J. Weiner et al. (J. Amer. Chem. SOC., 106,765 (1984). The parameters of our function are based on calculations on ethane, propane, n-butane, dimethyl ether, methyl ethyl ether, tetrahydrofuran, imidazole, indole, deoxyadenosine, base paired dinucleoside phosphates, adenine, guanine, uracil, cytosine, thymine, insulin, and myoglobin. We have also used these parameters to carry out the first general vibrational analysis of all five nucleic acid bases with a molecular mechanics potential approach.
Journal of molecular modeling, 2017
The roles of histone tails as substrates for reversible chemical modifications and dynamic cognate surfaces for the binding of regulatory proteins are well established. Despite these crucial roles, experimentally derived knowledge of the structure and possible binding sites of histone tails in chromatin is limited. In this study, we utilized molecular dynamics of isolated histone H3 N-terminal peptides to investigate its structure as a function of post-translational modifications that are known to be associated with defined chromatin states. We observed a structural preference for α-helices in isoforms associated with an inactive chromatin state, while isoforms associated with active chromatin states lacked α-helical content. The physicochemical effect of the post-translational modifications was highlighted by the interaction of arginine side-chains with the phosphorylated serine residues in the inactive isoform. We also showed that the isoforms exhibit different tail lengths, and, ...
2023
Full-length histone tails play a well characterized role in nucleosome core particles, and, as intrinsically disordered peptides, represent a current challenge for all-atom molecular dynamics simulations. Beyond the choice of the force field, the folding and the subsequent interactions with DNA landscape is complex and calls for a robust computational protocol capable of reproducibility. In this contribution, we assessed by a specifically tailored REST2-based simulation protocol the interaction between the four canonical histone tails and a DNA fragment from a canonical nucleosome core particles. We report contact maps obtained by clustering along several microseconds which prefigure plausible interactions between some of the positively-charged residues and DNA. Two major post-translational modifications of lysines are also discussed. Our work thus contributes to pave the way toward 1
Molecules (Basel, Switzerland), 2015
Protein arginine methyltransferases (PRMTs) catalyze the transfer of the methyl group from S-adenosyl-l-methionine (AdoMet) to arginine residues. There are three types of PRMTs (I, II and III) that produce different methylation products, including asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and monomethylarginine (MMA). Since these different methylations can lead to different biological consequences, understanding the origin of product specificity of PRMTs is of considerable interest. In this article, the quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) and free energy simulations are performed to study SDMA catalyzed by the Type II PRMT5 on the basis of experimental observation that the dimethylated product is generated through a distributive fashion. The simulations have identified some important interactions and proton transfers during the catalysis. Similar to the cases involving Type I PRMTs, a conserved Glu residue (Glu435) in P...
The journal of physical chemistry. B, 2015
Until now, atomistic simulations of DNA and RNA and their complexes have been executed using well calibrated but conceptually simple pair-additive empirical potentials (force fields). Although such simulations provided many valuable results, it is well established that simple force fields also introduce errors into the description, underlying the need for development of alternative anisotropic, polarizable molecular mechanics (APMM) potentials. One of the most abundant forces in all kinds on nucleic acids topologies is base stacking. Intra- and interstrand stacking is assumed to be the most essential factor affecting local conformational variations of B-DNA. However, stacking also contributes to formation of all kinds of non-canonical nucleic acids structures, such as quadruplexes or folded RNAs. The present study focuses on fourteen stacked cytosine (Cyt) dimers and the doubly H-bonded dimer. We evaluate the extent to which an APMM procedure, SIBFA, could account quantitatively for...
PMFF: Development of a Physics-Based Molecular Force Field for Protein Simulation and Ligand Docking
The Journal of Physical Chemistry B, 2020
The physics-based molecular force field (PMFF) was developed by integrating a set of potential energy functions in which each term in an intermolecular potential energy function is derived based on experimental values, such as the dipole moments, lattice energy, proton transfer energy, and X-ray crystal structures. The term "physics-based" is used to emphasize the idea that the experimental observables that are considered to be the most relevant to each term are used for the parameterization rather than parameterizing all observables together against the target value. PMFF uses MM3 intramolecular potential energy terms to describe intramolecular interactions and includes an implicit solvation model specifically developed for the PMFF. We evaluated the PMFF in three ways. We concluded that the PMFF provides reliable information based on the structure in a biological system and interprets the biological phenomena accurately by providing more accurate evidence of the biological phenomena.