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McDonald J, von Spakovsky MR, Reynolds WT. Predicting non-equilibrium folding behavior of polymer chains using the steepest-entropy-ascent quantum thermodynamic framework. J Chem Phys 2023; 158:104904. [PMID: 36922120 DOI: 10.1063/5.0137444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
The steepest-entropy-ascent quantum thermodynamic (SEAQT) framework is used to explore the influence of heating and cooling on polymer chain folding kinetics. The framework predicts how a chain moves from an initial non-equilibrium state to stable equilibrium along a unique thermodynamic path. The thermodynamic state is expressed by occupation probabilities corresponding to the levels of a discrete energy landscape. The landscape is generated using the Replica Exchange Wang-Landau method applied to a polymer chain represented by a sequence of hydrophobic and polar monomers with a simple hydrophobic-polar amino acid model. The chain conformation evolves as energy shifts among the levels of the energy landscape according to the principle of steepest entropy ascent. This principle is implemented via the SEAQT equation of motion. The SEAQT framework has the benefit of providing insight into structural properties under non-equilibrium conditions. Chain conformations during heating and cooling change continuously without sharp transitions in morphology. The changes are more drastic along non-equilibrium paths than along quasi-equilibrium paths. The SEAQT-predicted kinetics are fitted to rates associated with the experimental intensity profiles of cytochrome c protein folding with Rouse dynamics.
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Affiliation(s)
- Jared McDonald
- Materials Science and Engineering Department, Virginia Tech, Blacksburg, Virginia 24061, USA
| | | | - William T Reynolds
- Materials Science and Engineering Department, Virginia Tech, Blacksburg, Virginia 24061, USA
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2
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Abstract
Understanding peptide-surface interactions is crucial for programming self-assembly of peptides at surfaces and in realizing their applications, such as biosensors and biomimetic materials. In this study, we developed insights into the dependence of a residue's interaction with a surface on its neighboring residue in a tripeptide using molecular dynamics simulations. This knowledge is integral for designing rational mutations to control peptide-surface complexes. Using graphene as our model surface, we estimated the free energy of adsorption (ΔAads) and extracted predominant conformations of 26 tripeptides with the motif LNR-CR-Gly, where LNR and CR are variable left-neighboring and central residues, respectively. We considered a combination of strongly adsorbing (Phe, Trp, and Arg) and weakly adsorbing (Ala, Val, Leu, Ser, and Thr) amino acids on graphene identified in a prior study to form the tripeptides. Our results indicate that ΔAads of a tripeptide cannot be estimated as the sum of ΔAads of each residue indicating that the residues in a tripeptide do not behave as independent entities. We observed that the contributions from the strongly adsorbing amino acids were dominant, which suggests that such residues could be used for strengthening peptide-graphene interactions irrespective of their neighboring residues. In contrast, the adsorption of weakly adsorbing central residues is dependent on their neighboring residues. Our structural analysis revealed that the dihedral angles of LNR are more correlated with that of CR in the adsorbed state than in bulk state. Together with ΔAads trends, this implies that different backbone structures of a given CR can be accessed for a similar ΔAads by varying the LNR. Therefore, incorporation of context effects in designing mutations can lead to desired peptide structure at surfaces. Our results also emphasize that these cooperative effects in ΔAads and structure are not easily predicted a priori. The collective results have applications in guiding rational mutagenesis techniques to control orientation of peptides at surfaces and in developing peptide structure prediction algorithms in adsorbed state from its sequence.
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Affiliation(s)
- Siva Dasetty
- Department of Chemical & Biomolecular Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Sapna Sarupria
- Department of Chemical & Biomolecular Engineering, Clemson University, Clemson, South Carolina 29634, United States
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3
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Shi G, Wüst T, Landau DP. Elucidating thermal behavior, native contacts, and folding funnels of simple lattice proteins using replica exchange Wang-Landau sampling. J Chem Phys 2018; 149:164913. [PMID: 30384708 DOI: 10.1063/1.5026256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We studied the folding behavior of two coarse-grained, lattice models, the HP (hydrophobic-polar) model and the semi-flexible H0P model, whose 124 monomer long sequences were derived from the protein Ribonuclease A. Taking advantage of advanced parallel computing techniques, we applied replica exchange Wang-Landau sampling and calculated the density of states over the models entire energy ranges to high accuracy. We then determined both energetic and structural quantities in order to elucidate the folding behavior of each model completely. As a result of sufficiently long sequences and model complexity, yet computational accessibility, we were able to depict distinct free energy folding funnels for both models. In particular, we found that the HP model folds in a single-step process with a very highly degenerate native state and relatively flat low temperature folding funnel minimum. By contrast, the semi-flexible H0P model folds via a multi-step process and the native state is almost four orders of magnitude less degenerate than that for the HP model. In addition, for the H0P model, the bottom of the free energy folding funnel remains rough, even at low temperatures.
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Affiliation(s)
- Guangjie Shi
- Center for Simulational Physics, The University of Georgia, Athens, Georgia 30602-0002, USA
| | - Thomas Wüst
- Scientific IT Services, ETH Zurich, 8092 Zurich, Switzerland
| | - David P Landau
- Center for Simulational Physics, The University of Georgia, Athens, Georgia 30602-0002, USA
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Farris ACK, Shi G, Wüst T, Landau DP. The role of chain-stiffness in lattice protein models: A replica-exchange Wang-Landau study. J Chem Phys 2018; 149:125101. [PMID: 30278675 DOI: 10.1063/1.5045482] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using Monte Carlo simulations, we investigate simple, physically motivated extensions to the hydrophobic-polar lattice protein model for the small (46 amino acid) protein Crambin. We use two-dimensional replica-exchange Wang-Landau sampling to study the effects of a bond angle stiffness parameter on the folding and uncover a new step in the collapse process for particular values of this stiffness parameter. A physical interpretation of the folding is developed by analysis of changes in structural quantities, and the free energy landscape is explored. For these special values of stiffness, we find non-degenerate ground states, a property that is consistent with behavior of real proteins, and we use these unique ground states to elucidate the formation of native contacts during the folding process. Through this analysis, we conclude that chain-stiffness is particularly influential in the low energy, low temperature regime of the folding process once the lattice protein has partially collapsed.
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Affiliation(s)
- Alfred C K Farris
- Center for Simulational Physics, Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602, USA
| | - Guangjie Shi
- Center for Simulational Physics, Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602, USA
| | - Thomas Wüst
- Scientific IT Services, ETH Zürich, 8092 Zürich, Switzerland
| | - David P Landau
- Center for Simulational Physics, Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602, USA
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Luo MB, Ziebarth JD, Wang Y. Interplay of Coil-Globule Transition and Surface Adsorption of a Lattice HP Protein Model. J Phys Chem B 2014; 118:14913-21. [PMID: 25458556 PMCID: PMC4280116 DOI: 10.1021/jp506126d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
![]()
An
end-grafted hydrophobic-polar (HP) model protein chain with
alternating H and P monomers is studied to examine interactions between
the critical adsorption transition due to surface attraction and the
collapse transition due to pairwise attractive H–H interactions.
We find that the critical adsorption phenomenon can always be observed;
however, the critical adsorption temperature TCAP is influenced by the attractive H–H interactions
in some cases. When the collapse temperature Tc is lower than TCAP, the critical
adsorption of the HP chain is similar to that of a homopolymer without
intrachain attractions and TCAP remains
unchanged, whereas the collapse transition is suppressed by the adsorption.
In contrast, for cases where Tc is close
to or higher than TCAP, TCAP of the HP chain is increased, indicating that a collapsed
chain is more easily adsorbed on the surface. The strength of the
H–H attraction also influences the statistical size and shape
of the polymer, with strong H–H attractions resulting in adsorbed
and collapsed chains adopting two-dimensional, circular conformations.
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Affiliation(s)
- Meng-Bo Luo
- Department of Physics, Zhejiang University , Hangzhou 310027, P. R. China
| | - Jesse D Ziebarth
- Department of Chemistry, The University of Memphis , Memphis, Tennessee 38152, United States
| | - Yongmei Wang
- Department of Chemistry, The University of Memphis , Memphis, Tennessee 38152, United States
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Luettmer-Strathmann J, Binder K. Transitions of tethered chain molecules under tension. J Chem Phys 2014; 141:114911. [DOI: 10.1063/1.4895729] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Jutta Luettmer-Strathmann
- Department of Physics and Department of Chemistry, The University of Akron, Akron, Ohio 44325-4001, USA
| | - Kurt Binder
- Institut für Physik, Johannes-Gutenberg-Universität, Staudinger Weg 7, D-55099 Mainz, Germany
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7
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Shi G, Vogel T, Wüst T, Li YW, Landau DP. Effect of single-site mutations on hydrophobic-polar lattice proteins. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:033307. [PMID: 25314564 DOI: 10.1103/physreve.90.033307] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Indexed: 06/04/2023]
Abstract
We developed a heuristic method for determining the ground-state degeneracy of hydrophobic-polar (HP) lattice proteins, based on Wang-Landau and multicanonical sampling. It is applied during comprehensive studies of single-site mutations in specific HP proteins with different sequences. The effects in which we are interested include structural changes in ground states, changes of ground-state energy, degeneracy, and thermodynamic properties of the system. With respect to mutations, both extremely sensitive and insensitive positions in the HP sequence have been found. That is, ground-state energies and degeneracies, as well as other thermodynamic and structural quantities, may be either largely unaffected or may change significantly due to mutation.
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Affiliation(s)
- Guangjie Shi
- Center for Simulational Physics, The University of Georgia, Athens, Georgia 30602, USA
| | - Thomas Vogel
- Theoretical Division (T-1), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Thomas Wüst
- Scientific IT Services, ETH Zürich IT Services, 8092 Zürich, Switzerland
| | - Ying Wai Li
- National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - David P Landau
- Center for Simulational Physics, The University of Georgia, Athens, Georgia 30602, USA
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8
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Singh P, Sarkar SK, Bandyopadhyay P. Wang-Landau density of states based study of the folding-unfolding transition in the mini-protein Trp-cage (TC5b). J Chem Phys 2014; 141:015103. [DOI: 10.1063/1.4885726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Priya Singh
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi - 110 067, India
| | - Subir K. Sarkar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi - 110 067, India
| | - Pradipta Bandyopadhyay
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi - 110 067, India
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9
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Li Y, Wüst T, Landau D. Wang–Landau sampling of the interplay between surface adsorption and folding of HP lattice proteins. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2013.847273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Li YW, Wüst T, Landau DP. Generic folding and transition hierarchies for surface adsorption of hydrophobic-polar lattice model proteins. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:012706. [PMID: 23410358 DOI: 10.1103/physreve.87.012706] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 10/12/2012] [Indexed: 06/01/2023]
Abstract
The thermodynamic behavior and structural properties of hydrophobic-polar (HP) lattice proteins interacting with attractive surfaces are studied by means of Wang-Landau sampling. Three benchmark HP sequences (48mer, 67mer, and 103mer) are considered with different types of surfaces, each of which attract either all monomers, only hydrophobic (H) monomers, or only polar (P) monomers, respectively. The diversity of folding behavior in dependence of surface strength is discussed. Analyzing the combined patterns of various structural observables, such as, e.g., the derivatives of the numbers of surface contacts, together with the specific heat, we are able to identify generic categories of folding and transition hierarchies. We also infer a connection between these transition categories and the relative surface strengths, i.e., the ratio of the surface attractive strength to the interchain attraction among H monomers. The validity of our proposed classification scheme is reinforced by the analysis of additional benchmark sequences. We thus believe that the folding hierarchies and identification scheme are generic for HP proteins interacting with attractive surfaces, regardless of chain length, sequence, or surface attraction.
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Affiliation(s)
- Ying Wai Li
- Center for Simulational Physics, University of Georgia, Athens, Georgia 30602, USA.
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11
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Maerzke KA, Gai L, Cummings PT, McCabe C. Incorporating configurational-bias Monte Carlo into the Wang-Landau algorithm for continuous molecular systems. J Chem Phys 2012. [DOI: 10.1063/1.4766354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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12
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Wüst T, Landau DP. Optimized Wang-Landau sampling of lattice polymers: Ground state search and folding thermodynamics of HP model proteins. J Chem Phys 2012; 137:064903. [DOI: 10.1063/1.4742969] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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13
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Swetnam A, Allen MP. Selective adsorption of lattice peptides on patterned surfaces. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:062901. [PMID: 23005152 DOI: 10.1103/physreve.85.062901] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Indexed: 06/01/2023]
Abstract
To study the adsorption of individual peptides in implicit solvent, we propose a version of the Wang-Landau Monte Carlo algorithm that uses a single surface, with no need for a confining wall or grafting. Our "wall-free" method is both more efficient than the traditional ones and free of additional assumptions or approximations. We illustrate it by simulating an HP-model lattice peptide on planar surfaces with a variety of patterns of adsorption sites, discovering a temperature-induced switch of surface selection which is due to a balance of energetic and entropic effects.
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Affiliation(s)
- Adam Swetnam
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
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