scholarly journals Refining All-Atom Protein Force Fields for Polar-Rich, Prion-like, Low-Complexity Intrinsically Disordered Proteins

2020 ◽  
Vol 124 (43) ◽  
pp. 9505-9512
Author(s):  
Wai Shing Tang ◽  
Nicolas L. Fawzi ◽  
Jeetain Mittal
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Force Fields ◽  
Low Complexity ◽  
Disordered Proteins ◽  
Intrinsically Disordered ◽  
Protein Force Fields

scholarly journals Assemblages: Functional units formed by cellular phase separation

2014 ◽  
Vol 206 (5) ◽  
pp. 579-588 ◽  
Author(s):  
Jeffrey A. Toretsky ◽  
Peter E. Wright
Keyword(s):  
Phase Separation ◽  
Intrinsically Disordered Proteins ◽  
Intrinsic Disorder ◽  
Low Complexity ◽  
Disordered Proteins ◽  
Intracellular Space ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Disease States ◽  
Membrane Bound

The partitioning of intracellular space beyond membrane-bound organelles can be achieved with collections of proteins that are multivalent or contain low-complexity, intrinsically disordered regions. These proteins can undergo a physical phase change to form functional granules or other entities within the cytoplasm or nucleoplasm that collectively we term “assemblage.” Intrinsically disordered proteins (IDPs) play an important role in forming a subset of cellular assemblages by promoting phase separation. Recent work points to an involvement of assemblages in disease states, indicating that intrinsic disorder and phase transitions should be considered in the development of therapeutics.

scholarly journals Different force fields give rise to different amyloid aggregation pathways in molecular dynamics simulations

2020 ◽  
Author(s):  
Suman Samantray ◽  
Feng Yin ◽  
Batuhan Kav ◽  
Birgit Strodel
Keyword(s):  
Molecular Dynamics ◽  
Force Field ◽  
Intrinsically Disordered Proteins ◽  
Force Fields ◽  
Md Simulations ◽  
Peptide Sequence ◽  
Disordered Proteins ◽  
Test Case ◽  
Peptide Aggregation ◽  
Intrinsically Disordered

AbstractThe progress towards understanding the molecular basis of Alzheimers’s disease is strongly connected to elucidating the early aggregation events of the amyloid-β (Aβ) peptide. Molecular dynamics (MD) simulations provide a viable technique to study the aggregation of Aβ into oligomers with high spatial and temporal resolution. However, the results of an MD simulation can only be as good as the underlying force field. A recent study by our group showed that none of the force fields tested can distinguish between aggregation-prone and non-aggregating peptide sequences, producing the same and in most cases too fast aggregation kinetics for all peptides. Since then, new force fields specially designed for intrinsically disordered proteins such as Aβ were developed. Here, we assess the applicability of these new force fields to studying peptide aggregation using the Aβ16−22 peptide and mutations of it as test case. We investigate their performance in modeling the monomeric state, the aggregation into oligomers, and the stability of the aggregation end product, i.e., the fibrillar state. A main finding is that changing the force field has a stronger effect on the simulated aggregation pathway than changing the peptide sequence. Also the new force fields are not able to reproduce the experimental aggregation propensity order of the peptides. Dissecting the various energy contributions shows that AMBER99SB-disp overestimates the interactions between the peptides and water, thereby inhibiting peptide aggregation. More promising results are obtained with CHARMM36m and especially its version with increased protein–water interactions. It is thus recommended to use this force field for peptide aggregation simulations and base future reparameterizations on it.

The accuracy of force fields on the simulation of intrinsically disordered proteins: A benchmark test on the human p53 tumor suppressor

2020 ◽  
Vol 19 (04) ◽  
pp. 2050011
Author(s):  
Shangbo Ning ◽  
Jun Liu ◽  
Na Liu ◽  
Dazhong Yan
Keyword(s):  
Md Simulation ◽  
Intrinsically Disordered Proteins ◽  
Force Fields ◽  
Chemical Shifts ◽  
Disordered Proteins ◽  
Experimental Measurements ◽  
Intrinsically Disordered ◽  
Structural Ensembles ◽  
Water Models ◽  
Structural Ensemble

Intrinsically disordered proteins (IDPs) are a class of proteins without stable three-dimensional structures under physiological conditions. IDPs exhibit high dynamic nature and could be described by structural ensembles. As one of the most widely used tools, molecular dynamics (MD) simulation could provide the atomic descriptions of the structural ensemble of IDPs. However, the accuracy of the MD simulation largely depends on the accuracy of the force field. In this paper, we compared the structural ensembles of the activation domain 1 (AD1) in p53 tumor suppressor obtained from the widely used force fields, AMBER99SB-ILDN, CHARMM27, CHARMM36m with different water models. The results show that CHARMM36m generates more extended conformations than other force fields, while CHARMM27 prefers to sample the [Formula: see text]-helical structure. Moreover, the chemical shifts obtained by CHARMM36m are the closest to the experimental measurements. These results indicate that the CHARMM36m force field performs best in characterizing the structure properties of p53 AD1. Water models are also critical to describe the structural ensemble of IDPs. TIP4P water model can obtain more extended conformations and produce more local helical conformations than the TIP3P model in our simulation. In addition, we also compare the chemical shifts predicted by different chemical shift predicting programs with experimental measurements, the results show that SHIFTX2 obtains the best performance in the chemical shifts prediction.

Comparison and Evaluation of Force Fields for Intrinsically Disordered Proteins

2020 ◽  
Vol 60 (10) ◽  
pp. 4912-4923 ◽  
Author(s):  
Mueed Ur Rahman ◽  
Ashfaq Ur Rehman ◽  
Hao Liu ◽  
Hai-Feng Chen
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Force Fields ◽  
Disordered Proteins ◽  
Intrinsically Disordered

scholarly journals Advanced Sampling Methods for Multiscale Simulation of Disordered Proteins and Dynamic Interactions

Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1416
Author(s):  
Xiping Gong ◽  
Yumeng Zhang ◽  
Jianhan Chen
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Multiscale Simulation ◽  
Coarse Grained ◽  
Disordered Proteins ◽  
Dynamic Interactions ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Advanced Sampling ◽  
Protein Ensembles ◽  
Protein Force Fields

Intrinsically disordered proteins (IDPs) are highly prevalent and play important roles in biology and human diseases. It is now also recognized that many IDPs remain dynamic even in specific complexes and functional assemblies. Computer simulations are essential for deriving a molecular description of the disordered protein ensembles and dynamic interactions for a mechanistic understanding of IDPs in biology, diseases, and therapeutics. Here, we provide an in-depth review of recent advances in the multi-scale simulation of disordered protein states, with a particular emphasis on the development and application of advanced sampling techniques for studying IDPs. These techniques are critical for adequate sampling of the manifold functionally relevant conformational spaces of IDPs. Together with dramatically improved protein force fields, these advanced simulation approaches have achieved substantial success and demonstrated significant promise towards the quantitative and predictive modeling of IDPs and their dynamic interactions. We will also discuss important challenges remaining in the atomistic simulation of larger systems and how various coarse-grained approaches may help to bridge the remaining gaps in the accessible time- and length-scales of IDP simulations.

scholarly journals Molecular details of protein condensates probed by microsecond-long atomistic simulations

2020 ◽  
Author(s):  
Wenwei Zheng ◽  
Gregory L. Dignon ◽  
Xichen Xu ◽  
Roshan M. Regy ◽  
Nicolas L. Fawzi ◽  
...  
Keyword(s):  
Phase Separation ◽  
Intrinsically Disordered Proteins ◽  
Low Complexity ◽  
Coarse Grained ◽  
Disordered Proteins ◽  
Intrinsically Disordered ◽  
Residue Interaction ◽  
Coarse Grained Simulations ◽  
Protein Density

AbstractThe formation of membraneless organelles in cells commonly occurs via liquid-liquid phase separation (LLPS), and is in many cases driven by multivalent interactions between intrinsically disordered proteins (IDPs). Molecular simulations can reveal the specific amino acid interactions driving LLPS, which is hard to obtain from experiment. Coarse-grained simulations have been used to directly observe the sequence determinants of phase separation but have limited spatial resolution, while all-atom simulations have yet to be applied to LLPS due to the challenges of large system sizes and long time scales relevant to phase separation. We present a novel multiscale computational framework by obtaining initial molecular configurations of a condensed protein-rich phase from equilibrium coarse-grained simulations, and back mapping to an all-atom representation. Using the specialized Anton 2 supercomputer, we resolve microscopic structural and dynamical details of protein condensates through microsecond-scale all-atom explicit-solvent simulations. We have studied two IDPs which phase separate in vitro: the low complexity domain of FUS and the N-terminal disordered domain of LAF-1. Using this approach, we explain the partitioning of ions between phases with low and high protein density, demonstrate that the proteins are remarkably dynamic within the condensed phase, identify the key residue-residue interaction modes stabilizing the dense phase, all while showing good agreement with experimental observations. Our approach is generally applicable to all-atom studies of other single and multi-component systems of proteins and nucleic acids involved in the formation of membraneless organelles.

Sign in / Sign up

Export Citation Format

Share Document