Mobile random conformation

Its aqueous solutions are not only viscous but become gels over the temperature range 20 - 90 C. The course of sol-gel transition as a function of temperature monitored by optical rotation (25) suggests the conversion of a conformationally mobile random coil in the sol state to a rigid ordered conformation in the gel state. The midpoint of transition is approximately around 45 C. Only oriented, noncrystalline fibers could be prepared, the best of them at 45 C. 

The half-widths of 37-39 and 78-88 Hz, respectively, for the crystalline and amorphous phases are significantly larger than 18 and 38 Hz for those of the bulk-crystallized linear polyethylene (cf. Table 1). This is caused by incorporation of minor ethyl branches. The molecular alignment in the crystalline phase is slightly disordered, and the molecular mobility in the amorphous phase will therefore be promoted. With broadening of the crystalline and amorphous resonances, the resonance of the interphase also widens in comparison to that of bulk-crystallized linear polyethylene samples. This shows that the molecular conformation is more widely distributed from partially ordered trans-rich, conformation to complete random conformation, characteristic as the transition phase from the crystalline to amorphous regions. 

Annealing drawn crystalline polymer mobilizes the almost fully extended amorphous tie molecules that try to assume the thermodynamically required random conformations. The oriented crystalline sample shrinks if annealed with free ends, which permits the crystalline blocks in different microfibrils and connected by almost extended TTMs to move toward the position that they occupied before plastic deformation. Hence, the end-to-end distance or the fraction of TTMs in the amorphous region is reduced. Shrinkage rate of the samples is determined by competition of retractive forces of TTMs with the frictional forces or the van der Waals forces among neighbor fibers... 

Protein stability is just the difference in free energy between the correctly folded structure of a protein and the unfolded, denatured form. In the denatured form, the protein is unfolded, side chains and the peptide backbone are exposed to water, and the protein is conformationally mobile (moving around between a lot of different, random structures). The more stable the protein, the larger the free energy difference between the unfolded form and the native structure. 

A trend in the gas phase electron diffraction (ED) analyses is to supplement by MM calculations such inherent disadvantages as the scarcity of information, weak signal due to randomness, disorder, and conformational mobility of gaseous molecules. Hydrocarbons naturally provide the best material for such studies. Some recent... 

Recently, Schultes Spasic, Mohanty and Bartel studied in exquisite detail the effects of monovalent and divalent cations on the conformation order of random RNA sequences [115, 116]. These authors investigated the following questions Can arbitrary RNA sequences fold into a unique structure Is this is an evolutionary property of RNA sequences [115, 116] Schultes et al. utilized biochemical tools, such as lead ion induced cleavage, ultracentrifugation, and gel electrophoretic mobility, to probe the structure of evolved and random RNA sequences [115, 116]. 

Analysis of gel electrophoretic mobility data is based on the basic idea is that ordered sequences are compact. Compact molecules migrate faster in the gel matrix [115, 116]. But random RNA sequences have a disposition to acquire multiple conformations. Only some of these conformations may be compact [115, 116]. Furthermore, when the RNA constructs are run on gels in the presence of magnesium ions, some of the conformations undergo nonspecific collapse due to condensed counterions [115, 116]. 

On the other hand, when the electric held is strong, DNA is no longer considered to move as a random coil polymer, but moves with extended rodUke conformation. If DNA is completely extended and moves straight to the held direction, (hx ) = V, showing that the mobility in Eq. (7) is independent of DNA size ... 

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