Molecular springs

FIGURE 22.9 Schematic view demonstrating the mechanical equivalence between a Hller cluster and a series of soft and stiff molecular springs, representing bending-twisting and tension deformation of filler-filler bonds, respectively. (From Kluppel, M. and Heinrich, G., Kautschuk, Gummi, Kunststojfe, 58, 217, 2005. With permission.)... 

HTIN Thin-filament Extensible region binding Molecular spring... 

Segment contains tandem Ig repeats and PEVK repeats, both acting as molecular spring elements. This segment is extensively differentially spliced. In the shortest cardiac-specific N2B titin isoform (linked to inclusion of exon 49), exon 50 is spliced direcdy to exon 225. In more compliant cardiac and skeletal titin isoforms, exon 50 is spliced to exon 51 (linked to additional inclusion of exons in the segment 52-224). 

Labeit, D., Watanabe, K., and Witt, C. (2003). Calcium dependent molecular spring elements in the giant protein titin. Proc. Natl. Acad. Sci. USA Oct 30. 

Linke, W. A., Rudy, D. E., and Centner, T. (1999). I-band titin in cardiac muscle is a three-element molecular spring and is critical for maintaining thin filament structure./. Cell. Biol. 146, 631-644. 

According to this model, the clusters act as molecular springs with end to end distance , consisting of Nr backbone units of length d. The connectivity of the backbone units is characterized by the backbone fractal dimension dfjj. Due to the fractal nature of CCA-clusters it holds that... 

To better understand the nature and features of these vibrations, bonds can be considered as springs. Given this analogy, the behaviour of these molecular springs approximately follows Hooke s law of elasticity. In physics, Hooke s law relates the strain on a body (spring) to the force (load or mass) causing the strain . In essence, molecular bonds follow this linear relationship, where the... 

Syntheses and properties of heterohelicenes including thiophene rings as molecular springs 02YGK593. 

Rdhiig UF, Guidoni L, Laio A, Frank 1, Rothlisberger U (2004) A molecular spring for vision. J Am Chem Soc 126 15328-15329... 

Dratz EA, Holte LL. The molecular spring model for the function of docosahexaenoic acid (22 6w-3) in biological membranes. In 8inclair A, Gibson R, eds. Essential Fatty Acids and Eicosanoids. American Oil Chemists 8ociety, Champaign, IL, 1992, pp. 122-127. 

Fig. 8. Schematic of a molecular motor activated by intramolecular vibration energy relaxation of manifold A towards the rotor part of the motor. The rotor is positioned on an axis connected to reservoir 1 kept at a temperature T. Vibration manifold A is represented here by a simple molecular spring that can be excited by light or by the inelastic effect of a tunneling current passing through the molecular spring. Without such an excitation, manifold A is statistically populated by reservoir 1. A specific choice of a molecular structure equivalent to the spring may avoid its complete thermalization, for example by filtering the thermal noise giving rise to a unidirectional rotary motion...

Owing to the particular framework structure, the remarkable situation is met with that the entropy gain of dilution is counterbalanced by the entropy decrease bound up with the stretching of the molecular springs. This will set a limit to the swelling degree... 

On the basis of the molecular spring concept presented above, would one expect to find a correlation among the surface tensions of typical liquids and other intensive characteristics such as boiling point, and freezing point If so, support your point with some representative values from the literature. 

Pengo, P. Pasquato, L. Moro, S. Brigo, A. Fogolari, R Broxteiman, Q. B. Kaptein, B. Scrimin, P. Quantitative correlation of solvent polarity with the alpha-/3(10)-helix equilibrium a heptapeptide behaves as a solvent-driven molecular spring. Angew. Chem. Int. Ed. 2003, 42, 3388-3392. 

Stowell, M. H. B., Marks, B., Wigge, P., and McMahon, H. T. (1999). Nucleotide-dependent conformational changes in dynamin Evidence for a mechanochemical molecular spring. Nat. Cell Biol 1, 27-32. 

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