Motion detection Temperature Difference

Globular and membrane proteins in aqueous solution or Hpid bilayers/ biomembranes could undergo a wide range of motions at ambient temperatures. Such motions can be characterized by several types of NMR relaxation parameters, chemical exchange, dynamic interference including SRI [27—29]. Detection ranges for motions by the respective parameters are schematically illustrated in Fig. 1.1 for solution and soUd state NMR approaches. Naturally, fast motions are solely examined by solution NMR techniques for any portions of proteins. The experimental approaches to be able to detect intermediate or slow motions are obviously different between the solution and solid state NMR methods. 

On the tongue, the chemesthetic neurons are located in the papillae and are wrapped around the taste buds. The fungiform papillae, though lacking taste cells, possess chemesthetic neurons. These neurons make use of the structure of the taste bud to form a channel to the tongue surface. It has been reported that these neurons outnumber taste receptors nerves three to one [32]. The chemesthetic neurons are similar to taste receptors in that they have chemical specific receptors sites, however, they differ in that the neurons possess a set of other unique receptors. These receptors include mechanoreceptors for tactile response, thermoreceptors that detect temperature change, proprioceptors that detect motion, and nociceptors that mediate pain (comprise the somatosenses as a whole) [33]. 

To characterise the functionally Important motions in hydrated myoglobin, simulations on its hydrated CO complex have been performed by Steinbach and Brooks [35], In this study the temperature and hydration dependence of equilibrium dynamics was investigated. The authors performed two sets of MD simulations, torsionally restrained and unrestrained calculations on dehydrated carbonmonoxy myoglobin at different temperatures between 100 K and 400 K were compared to that on the hydrated protein. They found that the dehydrated protein exhibits almost exclusively harmonic fluctuations at all temperatures, while remarkable anharmonic motions have been detected in the hydrated protein at about 200 K independently whether the torsions were constrained. The... 

It is worth noting that solid state NMR is one of the preferred techniques for the detection of changes in the polymorphs with time or temperature. Also, the occurrence of internal motions or the presence of phase transitions can be easily assessed. In several cases (e.g. sulfatiazole [34]) SSNMR was able to resolve different polymorphs that were erroneously described by other techniques, probably because of compound stability and changing hydrated form. For all these reasons solid state NMR has been widely employed for the characterization of pharma-... 

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