Model proteins mechanical work

Chapter 16 applies thermodynamics to problems of biological interest. The metabolic processes leading to mechanical work performed by a living organism are described first, followed by discussions of the role of thermodynamics as a tool for understanding the stabilities of biopolymers such as proteins, and oligonucleotides as model compounds for DNA. 

Presented in Fig. 5 is a proposed mechanism for the action of aldolase which incorporates all of the data described above. Although some features of this proposed mechanism are speculative it does provide a working model which incorporates the stereochemical, chemical, kinetic, and other features elucidated by the many experiments described above. In this figure the protein cleft is approximated by the box drawn over the atoms which is open to solvent water on the top and far sides. In step A the conformation drawn is consistent with the fact that only the... 

Figure 1.7. Shown are the first reported data of the conversion by an elastic-contractile model protein of chemical energy due to an increase in concentration of acid into the mechanical work of contraction. A Length changes at constant force (isotonic contraction) in phosphate-buffered saline. B Force changes at constant length (isometric contraction) in phosphate-buffered saline. (Reproduced from Urry et al. )...

These results of 18 years ago, demonstrating the capacity of de wovo-designed model protein-based machines for the conversion of chemical energy into mechanical work, remain unex-... 

Key Molecular Players Perform Mechanical Work in Model Proteins... 

D.W. Urry, L.C. Hayes, and D. Channe Gowda, Electromechanical Transduction Reduction-driven Hydrophobic Folding Demonstrated in a Model Protein to Perform Mechanical Work. Biochem. Biophys. Res. Commun., 204,230-237, 1994. 

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. 

For the performance of mechanical work by model proteins cross-linked to form elastic bands, a weight is attached to the rubber-like... 

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. 

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