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arxiv: 1907.08784 · v1 · pith:EEYZLJA7new · submitted 2019-07-20 · ❄️ cond-mat.soft

Local symmetry determines the phases of linear chains: a simple model for the self-assembly of peptide

Pith reviewed 2026-05-24 18:51 UTC · model grok-4.3

classification ❄️ cond-mat.soft
keywords peptide self-assemblymarginally compact statessecondary structuresymmetry breakingsimple polymer modelshydrophobic effectbead-chain phases
0
0 comments X

The pith

Allowing partial interpenetration of consecutive beads in a tethered chain model produces marginally compact ground states that resemble α-helices and β-sheets.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper starts from a classic polymer model of spherical beads linked by tethers, subject to non-overlap constraints and square-well attractions that drive compaction. It shows that two successive local symmetry breaks change the phase diagram. First, permitting limited overlap between neighboring beads adds a new class of marginally compact states whose conformations echo the secondary-structure elements of proteins. Second, attaching a side sphere to each bead along a fixed direction breaks cylindrical symmetry and creates an additional phase inside the marginally compact regime that contains more elaborate secondary-structure assemblies. The work frames these outcomes as consequences of local geometric rules rather than detailed energetic terms.

Core claim

In a model of tethered spherical beads with steric non-overlap and pairwise square-well attractions, allowing partial interpenetration of consecutive beads produces a new class of marginally compact ground states comprising conformations reminiscent of α-helices and β-sheets; attaching side spheres along the negative normal further yields a novel phase with more complex secondary structure assemblies.

What carries the argument

Successive breaking of cylindrical symmetry through controlled partial interpenetration of consecutive beads and directed attachment of side spheres.

If this is right

  • The marginally compact regime now contains the basic building blocks of globular-protein native states.
  • A distinct sub-phase with richer secondary-structure motifs appears inside the marginally compact window.
  • The same local symmetry-breaking steps can be used to guide de novo design of self-assembled peptides.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Geometric constraints alone, without explicit directional bonds, can select protein-like motifs in ground-state ensembles.
  • Varying the attachment angle or side-sphere radius offers a direct route to map additional assembly phases.
  • The same symmetry-breaking logic may apply to other linear macromolecules whose compaction is governed by short-range attractions.

Load-bearing premise

A single square-well attraction together with the chosen side-sphere geometry and attachment direction suffice to capture the essential physics of the hydrophobic effect and side-chain packing.

What would settle it

Monte Carlo or molecular-dynamics runs that find only fully compact or fully extended states when partial interpenetration is allowed, or that recover no additional complex assemblies when side spheres are added, would falsify the reported phase sequence.

Figures

Figures reproduced from arXiv: 1907.08784 by Achille Giacometti, Amos Maritan, Jayanth Banavar, Tatjana Skrbic, Trinh X. Hoang.

Figure 1
Figure 1. Figure 1: FIG. 1: (a) Chain model. Each main chain sphere (cyan) has diameter [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2: Normalized histograms of the tilt angles of amino acids side chain with respect to the tangent (solid), [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3: (a) The heat capacity per monomer [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4: Results for a [PITH_FULL_IMAGE:figures/full_fig_p009_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5: Representative results in the elixir phase with [PITH_FULL_IMAGE:figures/full_fig_p010_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6: (a) The ground state phase diagram along the plane [PITH_FULL_IMAGE:figures/full_fig_p010_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: , after an initial sudden drop to a lower number of contacts, the chain starts to probe other possible favourable folds. In the process of doing this, the chain finds other possible folds belonging to the elixir phase, including those other four originally shown in Figure S2 (SI). This switching from one fold to another can be exploited in practical [PITH_FULL_IMAGE:figures/full_fig_p011_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8: The elixir phase for chain length (a) [PITH_FULL_IMAGE:figures/full_fig_p012_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: FIG. 9: Two ground state conformations of a chain in the elixir phase on changing the interaction range of the main [PITH_FULL_IMAGE:figures/full_fig_p014_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: FIG. 10: The helixI [PITH_FULL_IMAGE:figures/full_fig_p015_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: FIG. 11: Example of all- [PITH_FULL_IMAGE:figures/full_fig_p016_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: FIG. 12: Example of all- [PITH_FULL_IMAGE:figures/full_fig_p016_12.png] view at source ↗
Figure 13
Figure 13. Figure 13: FIG. 13: Example of all- [PITH_FULL_IMAGE:figures/full_fig_p017_13.png] view at source ↗
Figure 14
Figure 14. Figure 14: FIG. 14: Example of an all- [PITH_FULL_IMAGE:figures/full_fig_p017_14.png] view at source ↗
Figure 15
Figure 15. Figure 15: FIG. 15: Compatibility of the [PITH_FULL_IMAGE:figures/full_fig_p018_15.png] view at source ↗
Figure 16
Figure 16. Figure 16: FIG. 16: Changes in the values of the pitch [PITH_FULL_IMAGE:figures/full_fig_p019_16.png] view at source ↗
Figure 17
Figure 17. Figure 17: FIG. 17: Changes in the values of the distance [PITH_FULL_IMAGE:figures/full_fig_p020_17.png] view at source ↗
Figure 18
Figure 18. Figure 18: FIG. 18: Examples of comparison between ground state structures in the elixir phase and the native folds of [PITH_FULL_IMAGE:figures/full_fig_p021_18.png] view at source ↗
Figure 19
Figure 19. Figure 19: FIG. 19: (a) Comparison of the Root-mean-square-deviation (RMSD) from the native conformation of Protein [PITH_FULL_IMAGE:figures/full_fig_p022_19.png] view at source ↗
read the original abstract

We discuss the relation between the emergence of new phases with broken symmetry within the framework of simple models of biopolymers. We start with a classic model for a chain molecule of spherical beads tethered together, with the steric constraint that non-consecutive beads cannot overlap, and with a pairwise attractive square well potential accounting for the hydrophobic effect and promoting compaction. We then discuss the consequences of the successive breaking of spurious symmetries. First, we allow the partial interpenetration of consecutive beads. In addition to the standard high temperature coil phase and the low temperature collapsed phase, this results in a new class of marginally compact ground states comprising conformations reminiscent of $\alpha$-helices and $\beta$-sheets, the building blocks of the native states of globular proteins. We then discuss the effect of a further symmetry breaking of the cylindrical symmetry on attaching a side-sphere to the backbone beads along the negative normal of the chain, to mimic the presence of side chains in real proteins. This leads to the emergence of a novel phase within the previously obtained marginally compact phase, with the appearance of more complex secondary structure assemblies. The potential importance of this new phase in the \textit{de novo} design of self-assembled peptides is highlighted.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The paper constructs a minimal coarse-grained model of a linear chain of tethered spherical beads subject to a pairwise isotropic square-well attraction. Starting from the standard high-T coil and low-T collapsed phases, it first allows partial interpenetration of consecutive beads (breaking cylindrical symmetry) and reports the appearance of a new marginally compact ground-state class whose conformations are described as reminiscent of α-helices and β-sheets. A further symmetry breaking is introduced by attaching side spheres to each backbone bead along the negative normal; this is claimed to produce an additional novel phase inside the marginally compact regime that exhibits more complex secondary-structure assemblies. The work argues that these phases illustrate the role of local symmetry breaking in the self-assembly of peptides.

Significance. If the reported phases prove robust under quantitative structural criteria and parameter variation, the explicit geometric construction supplies a transparent illustration of how successive symmetry reductions can generate protein-like secondary-structure motifs from a single isotropic potential. The model’s reliance on a small set of geometric rules rather than fitted many-body terms is a clear strength and could inform minimal requirements for de novo peptide design.

major comments (2)
  1. [Abstract] Abstract and model-definition paragraphs: the central claim that partial bead interpenetration plus side-sphere attachment under a single isotropic square-well potential produces distinct, stable secondary-structure phases is load-bearing, yet no quantitative diagnostics (dihedral-angle distributions, hydrogen-bond geometry, contact-order statistics, or order parameters) are supplied to distinguish these conformations from visual analogies at chosen parameter values.
  2. [Model construction] Successive symmetry-breaking sections: the assertion that the isotropic square-well alone is sufficient (without directional or many-body terms) to stabilize the new phases rests on the chosen geometry; the manuscript does not test whether the reported ground states persist under small anisotropic perturbations to the potential or under modest changes in well width/depth, leaving open whether the phases are generic or artifacts of the specific parameter set.
minor comments (1)
  1. Notation for the negative-normal attachment direction and the precise definition of “partial interpenetration” should be given explicitly with a figure or equation reference to avoid ambiguity in reproduction.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive comments. We address each major point below.

read point-by-point responses
  1. Referee: [Abstract] Abstract and model-definition paragraphs: the central claim that partial bead interpenetration plus side-sphere attachment under a single isotropic square-well potential produces distinct, stable secondary-structure phases is load-bearing, yet no quantitative diagnostics (dihedral-angle distributions, hydrogen-bond geometry, contact-order statistics, or order parameters) are supplied to distinguish these conformations from visual analogies at chosen parameter values.

    Authors: We agree that the original presentation relies on visual characterization of representative ground-state conformations. In the revised manuscript we will add quantitative diagnostics, including dihedral-angle distributions for the helix-like states and contact-order statistics to distinguish the marginally compact phases from both the coil and fully collapsed regimes. revision: yes

  2. Referee: [Model construction] Successive symmetry-breaking sections: the assertion that the isotropic square-well alone is sufficient (without directional or many-body terms) to stabilize the new phases rests on the chosen geometry; the manuscript does not test whether the reported ground states persist under small anisotropic perturbations to the potential or under modest changes in well width/depth, leaving open whether the phases are generic or artifacts of the specific parameter set.

    Authors: The central result is the explicit geometric construction showing how successive local symmetry reductions generate the reported motifs from a single isotropic potential. While the manuscript does not contain systematic robustness tests, we will add a concise discussion of stability under modest variations of well width and depth (preserving the symmetry-breaking geometry) together with a brief note on the effect of small anisotropic perturbations that do not restore the broken symmetries. revision: yes

Circularity Check

0 steps flagged

No circularity: phases emerge from explicit model definitions and symmetry breakings

full rationale

The paper defines a sequence of models starting from a classic tethered-bead chain with steric constraints and isotropic square-well attraction, then successively relaxes cylindrical symmetry via partial bead interpenetration and adds side spheres along the negative normal. The reported marginally compact states and novel assemblies are presented as direct consequences of these geometric rules and the fixed potential; no equations reduce the phases to fitted parameters, self-cited uniqueness theorems, or prior ansatzes by the same authors. The derivation chain is therefore self-contained.

Axiom & Free-Parameter Ledger

3 free parameters · 2 axioms · 0 invented entities

The central claim rests on a small set of modeling choices whose values are not derived from first principles but chosen to produce compaction and secondary-structure motifs.

free parameters (3)
  • square-well depth and width
    Strength and range of the attractive potential chosen to drive compaction; values not stated in abstract.
  • bead radius and tether length
    Geometric parameters controlling steric constraints and chain connectivity.
  • side-sphere radius and attachment direction
    Parameters introduced to break cylindrical symmetry; direction fixed to negative normal.
axioms (2)
  • domain assumption Non-consecutive beads cannot overlap
    Standard excluded-volume constraint invoked to prevent chain crossing.
  • domain assumption Pairwise square-well attraction accounts for the hydrophobic effect
    Simplifying assumption stated in the abstract as the sole source of compaction.

pith-pipeline@v0.9.0 · 5765 in / 1478 out tokens · 23368 ms · 2026-05-24T18:51:43.254651+00:00 · methodology

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Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

  • IndisputableMonolith/Foundation/AlexanderDuality.lean alexander_duality_circle_linking (D=3 from linking) echoes
    ?
    echoes

    ECHOES: this paper passage has the same mathematical shape or conceptual pattern as the Recognition theorem, but is not a direct formal dependency.

    We then discuss the consequences of the successive breaking of spurious symmetries. First, we allow the partial interpenetration of consecutive beads... This results in a new class of marginally compact ground states comprising conformations reminiscent of α-helices and β-sheets... attaching a side-sphere... further reducing the uniaxial symmetry to biaxial... emergence of a novel phase... elixir phase

  • IndisputableMonolith/Foundation/AbsoluteFloorClosure.lean absolute_floor_iff_bare_distinguishability echoes
    ?
    echoes

    ECHOES: this paper passage has the same mathematical shape or conceptual pattern as the Recognition theorem, but is not a direct formal dependency.

    The notion of phases and singularities... Symmetry plays a key role in determining the nature of the ordered phase... spherical symmetry of the constituent objects has been broken by hand

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

63 extracted references · 63 canonical work pages

  1. [1]

    and conventional simulated annealing canonical Monte Carlo (MC) simulations [34, 35], always obtaining consis- tent results. In the Wang-Landau simulations, we sample polymer conformations according to the micro-canonical distribution by generating a sequence of chain conformations A→ B, and accepting the new configuration B with the micro-canonical accept...

  2. [2]

    Torsional order parameter τ Torsionτi, implicitly included in the discrete counterpart of the Frenet-Serret Eqs. (4), whose explicit definition can be given in terms of the derivative of ˆTi as τi = ( ˆTi׈T(1) i ) ·ˆT(2) i ⏐⏐⏐ˆT(1) i ׈T(2) i ⏐⏐⏐ 2 (8) where we have defined ˆT(n) i as the n-th (discrete) derivative of ˆTi. Here, a simple two (three) points...

  3. [3]

    Flatness order parameter A key feature of the β-sheet is to adopt a nearly two-dimensional conformation. Therefore we can distinguish it by computing a flatness order parameter ⟨ˆNi· (ˆNj׈Nk)⟩ = { ≈ 0 for a flat phase ̸= 0 otherwise (9) for all triplets i,j,k = 1,...,N of amino acids that are in the β phase. A value lower of ≈ 0.2 of the flatness order para...

  4. [4]

    Radius of gyration parameter An important order parameter is given by the mean square radius of gyration ⟨R2 g(T )⟩ that, as in conventional polymers, is able to distinguish between the coil (extended) phase, where the radius of gyration R2∼ N 2ν, with 2ν ≈ 1.2 and the globule (collapse) phase, where it is much smaller. In canonical simulations, this is d...

  5. [5]

    extended triple point

    Contact Maps According to the Levitt-Chothia classification [37], all known native states of globular proteins belong to four clearly defined classes: all-α having only α helix secondary structure, all-β having mainly β sheets, α +β where α helix and β sheet secondary structures do not mix but tend to segregate along the peptide chain, and α/β where convers...

  6. [6]

    Chaikin and T

    P. Chaikin and T. Lubensky, Principles of Condensed Matter Physics . Cambridge University Press, 2000

  7. [7]

    Hansen and I

    J. Hansen and I. McDonald, Theory of Simple Liquids . Elsevier Science, 2006

  8. [8]

    C. R. Cantor and P. R. Schimmel, Biophysical Chemistry: Part II: The Behavior of Biological Macromolecules (Their Biophysical Chemistry; PT. 2) . W. H. Freeman, 1 ed., 6 1980

  9. [9]

    A. V. Finkelstein and O. Ptitsyn, Protein Physics, Second Edition: A Course of Lectures (Soft Condensed Matter, Complex Fluids and Biomaterials) . Academic Press, 2 ed., 7 2016

  10. [10]

    The structure of synthetic polypeptides,

    L. Pauling and R. B. Corey, “The structure of synthetic polypeptides,” Proceedings of the National Academy of Science of the United States of America , vol. 37, pp. 205–211, 1951

  11. [11]

    Configurations of Polypeptide Chains With Favored Orientations Around Single Bonds: Two New Pleated Sheets,

    L. Pauling and R. B. Corey, “Configurations of Polypeptide Chains With Favored Orientations Around Single Bonds: Two New Pleated Sheets,” Proceedings of the National Academy of Science of the United States of America, vol. 37, pp. 729–740, 1951

  12. [12]

    The coming of age of de novo protein design,

    P.-S. Huang, S. E. Boyken, and D. Baker, “The coming of age of de novo protein design,” Nature, vol. 537, pp. 320–327, SEP 15 2016. 24

  13. [13]

    Design of coiled-coil protein-origami cages that self-assemble in vitro and in vivo,

    A. Ljubetic, F. Lapenta, H. Gradisar, I. Drobnak, J. Aupic, Z. Strmsek, D. Lainscek, I. Hafner-Bratkovic, A. Majerle, N. Krivec, M. Bencina, T. Pisanski, T. C. Velickovic, A. Round, J. Maria Carazo, R. Melero, and R. Jerala, “Design of coiled-coil protein-origami cages that self-assemble in vitro and in vivo,” Nature Biotechnology, vol. 35, p. 1094, NOV 2017

  14. [14]

    De novo design of self-assembling helical protein filaments,

    H. Shen, J. A. Fallas, E. Lynch, W. Sheffler, B. Parry, N. Jannetty, J. Decarreau, M. Wagenbach, J. J. Vicente, J. Chen, et al., “De novo design of self-assembling helical protein filaments,” Science, vol. 362, no. 6415, pp. 705–709, 2018

  15. [15]

    Recent advances of self-assembling peptide-based hydrogels for biomedical applications,

    J. Li, R. Xing, S. Bai, and X. Yan, “Recent advances of self-assembling peptide-based hydrogels for biomedical applications,” Soft Matter, vol. 15, pp. 1704–1715, 2019

  16. [16]

    Rigid helical-like assemblies from a self-aggregating tripeptide,

    S. Bera, S. Mondal, B. Xue, L. J. Shimon, Y. Cao, and E. Gazit, “Rigid helical-like assemblies from a self-aggregating tripeptide,” Nature Materials, p. 1, 2019

  17. [17]

    de Gennes, Scaling Concepts in Polymer Physics

    P. de Gennes, Scaling Concepts in Polymer Physics . Cornell University Press, 1979

  18. [18]

    A. R. Khokhlov, A. Y. Grosberg, and V. S. Pande,Statistical Physics of Macromolecules (Polymers and Complex Materials). American Institute of Physics, 3 1994

  19. [19]

    Rubinstein and R

    M. Rubinstein and R. H. Colby, Polymer Physics (Chemistry) . Oxford University Press, 1 ed., 6 2003

  20. [20]

    Phase transitions of a single polymer chain: A Wang-Landau simulation study,

    M. P. Taylor, W. Paul, and K. Binder, “Phase transitions of a single polymer chain: A Wang-Landau simulation study,” The Journal of Chemical Physics , vol. 131, p. 114907, SEP 21 2009

  21. [21]

    From polymers to proteins: the effect of side chains and broken symmetry on the formation of secondary structures within a Wang-Landau approach,

    T. Skrbic, A. Badasyan, T. X. Hoang, R. Podgornik, and A. Giacometti, “From polymers to proteins: the effect of side chains and broken symmetry on the formation of secondary structures within a Wang-Landau approach,” Soft Matter , vol. 12, no. 21, pp. 4783–4793, 2016

  22. [22]

    Optimal shapes of compact strings,

    A. Maritan, C. Micheletti, A. Trovato, and J. Banavar, “Optimal shapes of compact strings,”Nature, vol. 406, pp. 287–290, JUL 20 2000

  23. [23]

    Global curvature, thickness, and the ideal shapes of knots,

    O. Gonzalez and J. Maddocks, “Global curvature, thickness, and the ideal shapes of knots,” Proceedings of the National Academy of Sciences of the United States , vol. 96, pp. 4769–4773, APR 27 1999

  24. [24]

    Mathematics - Best packing in proteins and DNA,

    A. Stasiak and J. Maddocks, “Mathematics - Best packing in proteins and DNA,” Nature, vol. 406, pp. 251–253, JUL 20 2000

  25. [25]

    Folding, design, and determination of interaction potentials using off-lattice dynamics of model heteropolymers,

    C. Clementi, A. Maritan, and J. Banavar, “Folding, design, and determination of interaction potentials using off-lattice dynamics of model heteropolymers,” Physical Review Letters, vol. 81, pp. 3287–3290, OCT 12 1998

  26. [26]

    Structure and aggregation of a helix-forming polymer,

    J. E. Magee, Z. Song, R. A. Curtis, and L. Lue, “Structure and aggregation of a helix-forming polymer,” The Journal of Chemical Physics, vol. 126, p. 144911, APR 14 2007

  27. [27]

    First-principles design of nanomachines,

    J. R. Banavar, M. Cieplak, T. X. Hoang, and A. Maritan, “First-principles design of nanomachines,” Proceedings of the National Academy of Science of the United States of America , vol. 106, pp. 6900–6903, APR 28 2009

  28. [28]

    A Coarse-Grained Approach to Protein Design: Learning from Design to Understand Folding,

    I. Coluzza, “A Coarse-Grained Approach to Protein Design: Learning from Design to Understand Folding,” PLoS ONE, vol. 6, p. e20853, JUL 1 2011

  29. [29]

    Effective stiffness and formation of secondary structures in a protein-like model,

    T. Skrbic, T. X. Hoang, and A. Giacometti, “Effective stiffness and formation of secondary structures in a protein-like model,” The Journal of Chemical Physics , vol. 145, p. 084904, AUG 28 2016

  30. [30]

    On the Pseudo Phase Diagram of Single Semi-Flexible Polymer Chains: A Flat-HistogramMonte Carlo Study,

    B. Werlich, M. P. Taylor, T. Shakirov, and W. Paul, “On the Pseudo Phase Diagram of Single Semi-Flexible Polymer Chains: A Flat-HistogramMonte Carlo Study,” Polymers, vol. 9, p. 38, FEB 2017

  31. [31]

    The elixir phase of chain molecules,

    T. Skrbic, T. X. Hoang, A. Maritan, J. R. Banavar, and A. Giacometti, “The elixir phase of chain molecules,” Proteins, vol. 87, no. 3, pp. 176–184, 2019

  32. [32]

    What is life? part ii,

    G. D. Rose, “What is life? part ii,” Proteins, vol. 87, no. 3, pp. 174–175, 2019

  33. [33]

    Coxeter, Introduction to geometry

    H. Coxeter, Introduction to geometry. Wiley classics library, Wiley, 1969

  34. [34]

    Conformation of Polypeptide Chains,

    G. Ramachandran and V. Sasisekharan, “Conformation of Polypeptide Chains,” Advances in Protein Chemistry , vol. 23, pp. 283–437, 1968

  35. [35]

    A backbone-based theory of protein folding,

    G. D. Rose, P. J. Fleming, J. R. Banavar, and A. Maritan, “A backbone-based theory of protein folding,” Proceedings of the National Academy of Sciences of the United States of America , vol. 103, pp. 16623–16633, NOV 7 2006

  36. [36]

    Ramachandran maps for side chains in globular proteins,

    G. D. Rose, “Ramachandran maps for side chains in globular proteins,” Proteins, vol. 87, no. 5, pp. 357–364, 2019

  37. [37]

    The geometry of soft materials: a primer,

    R. Kamien, “The geometry of soft materials: a primer,” Reviews of Modern Physics , vol. 74, pp. 953–971, OCT 2002

  38. [38]

    Efficient, multiple-range random walk algorithm to calculate the density of states,

    F. Wang and D. Landau, “Efficient, multiple-range random walk algorithm to calculate the density of states,” Physical Review Letters, vol. 86, pp. 2050–2053, MAR 5 2001

  39. [39]

    M. P. Allen and D. J. Tildesley,Computer Simulation of Liquids (Oxford Science Publications). Clarendon Press, reprint ed., 6 1989

  40. [40]

    Frenkel and B

    D. Frenkel and B. Smit, Understanding Molecular Simulation, Second Edition: From Algorithms to Applications (Compu- tational Science Series, Vol 1) . Academic Press, 2 ed., 11 2001

  41. [41]

    Energetics of hydrogen bonds in peptides,

    S.-Y. Sheu, D.-Y. Yang, H. L. Selzle, and E. W. Schlag, “Energetics of hydrogen bonds in peptides,” Proceedings of the National Academy of Sciences , vol. 100, no. 22, pp. 12683–12687, 2003

  42. [42]

    Structural patterns in globular proteins,

    M. Levitt and C. Chothia, “Structural patterns in globular proteins,” Nature, vol. 261, no. 5561, pp. 552–558, 1976

  43. [43]

    Geometry of proteins: Hydrogen bonding, sterics, and marginally compact tubes,

    J. Banavar, M. Cieplak, A. Flammini, T. Hoang, R. Kamien, T. Lezon, D. Marenduzzo, A. Maritan, F. Seno, Y. Snir, and A. Trovato, “Geometry of proteins: Hydrogen bonding, sterics, and marginally compact tubes,” Physical Review E , vol. 73, p. 031921, MAR 2006

  44. [44]

    Folding of polymer chains with short-range binormal interactions,

    A. Craig and E. Terentjev, “Folding of polymer chains with short-range binormal interactions,” Journal of Physics A: Mathematical and General, vol. 39, pp. 4811–4828, MAY 5 2006

  45. [45]

    Hybrid Particle-Field Model for Conformational Dynamics of Peptide Chains,

    S. L. Bore, G. Milano, and M. Cascella, “Hybrid Particle-Field Model for Conformational Dynamics of Peptide Chains,” Journal of Chemical Theory and Computation , vol. 14, pp. 1120–1130, FEB 2018

  46. [46]

    Protein structure determination using metagenime sequence data,

    S. Ovchinnikov, H. Park, N. Vaghese, P. Huang, G. Pavlopoulos, D. Kim, H. Kamisetty, N. Kyrpides, and D. Baker, “Protein structure determination using metagenime sequence data,” Science, vol. 355, pp. 294–298, JUAN 20 2017. 25

  47. [47]

    Atomic-Level Characterization of the Structural Dynamics of Proteins,

    D. Shaw, P. Maragakis, K. Lindorff-Larsen, S. Piana, R. Dror, M. Eastwood, J. Bank, J. Jumper, J. Salmon, Y. Shan, and W. Wriggers, “Atomic-Level Characterization of the Structural Dynamics of Proteins,” Science, vol. 330, pp. 341–346, OCT 15 2010

  48. [48]

    An Algorithm for Protein Helix Assignment Using Helix Geometry,

    C. Cao, S. Xu, and L. Wang, “An Algorithm for Protein Helix Assignment Using Helix Geometry,” PLoS ONE, vol. 10, p. e0129674, JUL 1 2015

  49. [49]

    The role of directional interactions in the designability of generalized heteropolymers ,

    C. Cardelli, V. Bianco, L. Rovigatti, F. Nerattini, L. Tubiana, C. Dellago, and I. Coluzza, “The role of directional interactions in the designability of generalized heteropolymers ,” Scientific Reports, vol. 8, p. 4592, MAR 12 2018

  50. [50]

    An Accurate Model for Biomolecular Helices and Its Application to Helix Visualization,

    L. Wang, H. Qiao, C. Cao, S. Xu, and S. Zou, “An Accurate Model for Biomolecular Helices and Its Application to Helix Visualization,” PLoS ONE, vol. 10, p. e0129653, JUN 30 2015

  51. [51]

    Fast procedure for reconstruction of full-atom protein models from reduced representations,

    P. Rotkiewicz and J. Skolnick, “Fast procedure for reconstruction of full-atom protein models from reduced representations,” Journal of Computational Chemistry , vol. 29, pp. 1460–1465, JUL 15 2008

  52. [52]

    Molten globules, entropy-driven conformational change and protein folding,

    R. L. Baldwin and G. D. Rose, “Molten globules, entropy-driven conformational change and protein folding,” Current Opinion in Structural Biology , vol. 23, pp. 4–10, FEB 2013

  53. [53]

    Theory of protein folding,

    J. Onuchic and P. Wolynes, “Theory of protein folding,” Current Opinion in Structural Biology , vol. 14, pp. 70–75, 2004

  54. [54]

    GROMACS - A Message-passing parallel molecular-dynamics imple- mentation,

    H. Berensen, D. Vanderspoel, and R. Vandrunen, “GROMACS - A Message-passing parallel molecular-dynamics imple- mentation,” Computer Physics Communications , vol. 91, pp. 43–56, SEP 1995

  55. [55]

    GROMACS 4: Algorithms for highly efficient, load-balanced, and scalable molecular simulation,

    B. Hess, C. Kutzner, D. van der Spoel, and E. Lindahl, “GROMACS 4: Algorithms for highly efficient, load-balanced, and scalable molecular simulation,” Journal of Chemical Theory and Computation , vol. 4, pp. 435–447, MAR 2008

  56. [56]

    Contact order, transition state placement and the refolding rates of single domain proteins,

    K. Plaxco, K. Simons, and D. Baker, “Contact order, transition state placement and the refolding rates of single domain proteins,” Journal of Molecular Biology , vol. 277, pp. 985–994, APR 10 1998

  57. [57]

    Contact order and ab initio protein structure prediction,

    R. Bonneau, I. Ruczinski, J. Tsai, and D. Baker, “Contact order and ab initio protein structure prediction,” Protein Science, vol. 11, pp. 1937–1944, AUG 2002

  58. [58]

    Characterization of the nucleation barriers for protein aggregation and amyloid formation,

    S. Auer, C. M. Dobson, and M. Vendruscolo, “Characterization of the nucleation barriers for protein aggregation and amyloid formation,” HFSP Journal, vol. 1, pp. 137–146, JUL 2007

  59. [59]

    The case for defined protein folding pathways,

    S. W. Englander and L. Mayne, “The case for defined protein folding pathways,” Proceedings of the National Academy of Science of the United States of America , vol. 114, pp. 8253–8258, AUG 1 2017

  60. [60]

    Clash between energy landscape theory and foldon-dependent protein folding,

    R. L. Baldwin, “Clash between energy landscape theory and foldon-dependent protein folding,” Proceedings of the National Academy of Science of the United States of America , vol. 114, pp. 8442–8443, AUG 8 2017

  61. [61]

    Colloquium: Toward living matter with colloidal particles,

    Z. Zeravcic, V. N. Manoharan, and M. P. Brenner, “Colloquium: Toward living matter with colloidal particles,” Review of Modern Physics , vol. 89, p. 031001, SEP 13 2017

  62. [62]

    Chiral colloidal clusters,

    D. Zerrouki, J. Baudry, D. Pine, P. Chaikin, and J. Bibette, “Chiral colloidal clusters,” Nature, vol. 455, pp. 380–382, SEP 18 2008

  63. [63]

    Universal folding pathways of polyhedron nets,

    P. M. Dodd, P. F. Damasceno, and S. C. Glotzer, “Universal folding pathways of polyhedron nets,” Proceedings of the National Academy of Sciences of the United States of America , vol. 115, pp. E6690–E6696, JUL 17 2018