Elastic Entropic Forces in Polymer Deformation

Kartsovnik, V.I.; Volchenkov, Dimitri

doi:10.3390/e24091260

Cited by 7 publications

(3 citation statements)

References 44 publications

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“…However, it is important to note that any restriction on chain configurations results in an entropic force, so compressing a molecular chain also gives rise to forces driven by entropy [35,36]. Although the concept of entropic spring originates from polymer physics, which is particularly concerned with elasticity [37,38], this concept has attracted much interest in molecular biology, being applied for explaining fast antibody fragment motion [39], conformational coupling mechanism in the ABC transporters [40], modulation of integrin activation [41], and the force-extension behavior in cardiac titin protein that prevents sarcomere overstretching [42]. Entropic springs have also been identified as functions of intrinsically disordered regions in proteins [43] and were even used to explain more fundamental questions, such as solving the Gibbs paradox [44].…”

Section: Discussionmentioning

confidence: 99%

Intact Transition Epitope Mapping—Force Interferences by Variable Extensions (ITEM-FIVE)

Koy,

Röwer,

Thiesen

et al. 2024

Biomolecules

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Investigations on binding strength differences of non-covalent protein complex components were performed by mass spectrometry. T4 fibritin foldon (T4Ff) is a well-studied miniprotein, which together with its biotinylated version served as model system to represent a compactly folded protein to which an Intrinsically Disordered Region (IDR) was attached. The apparent enthalpies of the gas phase dissociation reactions of the homo-trimeric foldon F-F-F and of the homo-trimeric triply biotinylated foldon bF-bF-bF have been determined to be rather similar (3.32 kJ/mol and 3.85 kJ/mol) but quite distinct from those of the singly and doubly biotinylated hetero-trimers F-F-bF and F-bF-bF (1.86 kJ/mol and 1.08 kJ/mol). Molecular dynamics simulations suggest that the ground states of the (biotinylated) T4Ff trimers are highly symmetric and well comparable to each other, indicating that the energy levels of all four (biotinylated) T4Ff trimer ground states are nearly indistinguishable. The experimentally determined differences and/or similarities in enthalpies of the complex dissociation reactions are explained by entropic spring effects, which are noticeable in the T4Ff hetero-trimers but not in the T4Ff homo-trimers. A lowering of the transition state energy levels of the T4Ff hetero-trimers seems likely because the biotin moieties, mimicking intrinsically disordered regions (IDRs), induced asymmetries in the transition states of the biotinylated T4Ff hetero-trimers. This transition state energy level lowering effect is absent in the T4Ff homo-trimer, as well as in the triply biotinylated T4Ff homo-trimer. In the latter, the IDR-associated entropic spring effects on complex stability cancel each other out. ITEM-FIVE enabled semi-quantitative determination of energy differences of complex dissociation reactions, whose differences were modulated by IDRs attached to compactly folded proteins.

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Section: Discussionmentioning

confidence: 99%

Intact Transition Epitope Mapping—Force Interferences by Variable Extensions (ITEM-FIVE)

Koy,

Röwer,

Thiesen

et al. 2024

Biomolecules

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“…In contrast, the chains that form the hidden length at a given instant will tend to relax in accordance with their elastomeric behaviors. The combination of an elastomeric phase and a viscous (dissipative) medium establishes the conditions for any material to exhibit viscoelasticity [ 61 ], and may be identified through the characteristic hysteresis observed in this type of materials when subjected to unloading-reloading cycles [ 62 ]. A scheme of the interplay between the different microstructural elements during the loading-unloading cycles is presented in Figure 10 .…”

Section: Discussionmentioning

confidence: 99%

Variation in the Elastic Modulus and Increased Energy Dissipation Induced by Cyclic Straining of Argiope bruennichi Major Ampullate Gland Silk

Jiang

et al. 2023

Biomimetics

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The trends exhibited by the parameters that describe the mechanical behaviour of major ampullate gland silk fibers spun by Argiope bruennichi spiders is explored by performing a series of loading-unloading tests at increasing values of strain, and by the subsequent analysis of the true stress-true strain curves obtained from these cycles. The elastic modulus, yields stress, energy absorbed, and energy dissipated in each cycle are computed in order to evaluate the evolution of these mechanical parameters with this cyclic straining. The elastic modulus is observed to increase steadily under these loading conditions, while only a moderate variation is found in the yield stress. It is also observed that a significant proportion of the energy initially absorbed in each cycle is not only dissipated, but that the material may recover partially from the associated irreversible deformation. This variation in the mechanical performance of spider silk is accounted for through a combination of irreversible and reversible deformation micromechanisms in which the viscoelasticity of the material plays a leading role.

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“…Meerts et al stated that as the load increases, the short-range gluten-starch and starch-starch interactions in the dough begin to break down to the point where eventually only the long-range glutengluten interactions remain to provide structural integrity to the material [12,13]. Especially when considering the reversible entropy-elastic behavior of entangled polymers, wheat flour dough can be compared with other polymeric networks when a load is applied, and strain hardening occurs [14]. The breaking, or the shift, of molecular bonds under load is a widespread polymeric behavior.…”

Section: Introductionmentioning

confidence: 99%

Structure Strengthening Phenomena of Gluten Matrices under Different Stress Types

Vidal,

Alpers,

Becker

2023

Polymers

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To predict the achievable product volume with respect to the gas retention capacity of the gluten matrix in wheat flour doughs, strain hardening evaluation is crucial. But assessing these structure hardening phenomena in wheat flour dough systems is still a challenging task. In this work, a simple shear method applied to kneaded dough samples was tested and compared to biaxial extension tests performed with a lubricated squeezing flow method. The comparability of shear-induced structure hardening with biaxial extension tests was shown. Structure hardening and breakdown after overload were visualized using shear flow and a comparison of the obtained shear flow over Hencky strain curve peaks. To predict the behavior of the analyzed flours according to their composition, a correlation analysis of the flour and dough properties was performed. The influence of the HMW glutenin subunits on the sensitivity of the dough matrix according to the applied shear speed (0.1 and 1.0 mm/s) could be shown with a correlation coefficient of 0.94. The LMW glutenin subunits, on the other hand, showed a high correlation coefficient of 0.89 with the achievable network connectivity parameter z [-] gained from frequency sweep testing.

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Elastic Entropic Forces in Polymer Deformation

Cited by 7 publications

References 44 publications

Intact Transition Epitope Mapping—Force Interferences by Variable Extensions (ITEM-FIVE)

Intact Transition Epitope Mapping—Force Interferences by Variable Extensions (ITEM-FIVE)

Variation in the Elastic Modulus and Increased Energy Dissipation Induced by Cyclic Straining of Argiope bruennichi Major Ampullate Gland Silk

Structure Strengthening Phenomena of Gluten Matrices under Different Stress Types

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