Model proteins elasticity

Designed elastic model proteins exhibit diverse Junctions that mimic biological functions by diverse means of controlling association of oillike domains. As a result, five experimentally derived axioms phenomenologically categorize means by which energy conversions occur through control of association of oil-like domains. 

The particular designed elastic model proteins, through which the mechanistic assertion developed, use a repeating five-amino-acid residue sequence propagated by translational symmetry. Of the five axioms noted above under the phenomenological assertion, the fifth axiom describes the conditions for increased positive cooperativity and the result of increased effi-... 

These elastic model proteins exhibit remarkable biocompatibility due to an elasticity different from that of disordered petroleum-based elastomers and natural latex rubbers. 

These elastic model proteins form regular dynamic structures that exhibit mechanical resonances at low frequencies. 

Consequently, soft tissue restoration becomes a manifest area of application of elastic model proteins. 

Synthetic elastic tubes formed from elastic model protein can match the elastic properties of the natural artery. 

Drugs, containing charge, pair with oppositely charged vinegar-like groups of the elastic model protein. 

Using atomic force microscopy, it is possible to obtain the smooth force-extension profile of a single elastic model protein chain. 

Insertion of a globular protein sensing element within an elastic model protein chain results in a force-extension profile that contains the unfolding peak for the single globular protein. 

As a test of this perspective, we prepared elastic model proteins with and without cell attachment sequences and cross-linked them to form elastic sheets called bioelastic matrices. Cells do not adhere to these matrices without the cell attachment sequences cells do adhere to the bioelastic matrices containing the cell attachment sequences, as depicted in Figure 2.20. Furthermore, the cells spread out and grew to completely cover the surface. Perhaps even more significantly, cyclic stretching of the... 

The atomic force microscopy (AFM) singlechain force-extension studies on the elastic model proteins demonstrate entropic elastic-... 

Now, cross-linking the elastic model protein in the phase-separated state results in elastic bands. Similarly warming the band, swollen at room temperature (just below T,), to body temperature (some 15 degrees above T,) causes the band to contract with the performance of mechanical work. The band pumps iron on raising the temperature from below to above T,. As scientific accounts go, the T, perspective exemplifies simplicity. 

Figure 5.13. A procedure for the formation of elastic model proteins into y-irradiation cross-linked sheets for characterization as elastic-contractile systems for performance of mechemical work of lifting a weight.

Figure 5.14. Sheet of elastic model protein of y-irradiation cross-linked (GVGVP)25i as demonstrated in Figure 5.13 directly usable in thermally driven contraction and in chemically driven contraction.

Axiom 2 Heating to raise the temperature from below to above the temperature interval for hydrophobic association of cross-linked elastic model protein chains drives contraction with the performance of mechanical work. 

Figure 5.23. Mechano-chemical transduction exhibited by carboxyl-containing cross-linked elastic model protein (A) Stretch gives nonlinear increases in pKa values despite the linear stress-strain curve...

Figure 5.29. Stretch-induced pKa shift within hydrophobically associated elastic model protein implies competition for hydration between carboxy-late and hydrophobic groups. Despite water uptake into the model elastic protein on stretching, the COO" experiences less accessible hydration. The implication is that hydrophobic hydration, formed due to exposed hydrophobic groups on extension, is unsuited for COO" hydration. (Reproduced with permission from Urry et al. )...

Figure 5.34. Acid-base titration curves of the series of elastic Model Proteins I and i through v of Table 5.5 that exhibit systematic increases in hydrophobic-induced pK shifts and positive cooperativity resulting from competition for hydration between apolar and polar groups. (Inset) Slope of the Henderson-Hasselbalch equation with n = 1, and the slopes for...

The presence of positive cooperativity, explained by the interconversion between different conformational states, also demonstrates that these entropic elastic model proteins are not properly described as random chain networks, as the adherents of the relevance of the classical theory of rubber elasticity to protein elasticity are compelled to argue. 

Positive Cooperativity of Carboxyl Ionization in Elastic Model Proteins Increases with Increasing Hydrophobicity... 

Z.2 The Phase Diagram of the Elastic Model Protein (GVGVP)2si... 

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