Solvent-induced conformational changes

Loo, J. A. Loo, R. R. O. Udseth, H. R. Edmonds, C. G. Smith, R. D. Solvent-induced conformational-changes of polypeptides probed by electrospray-ionization mass-spectrometry. Rapid Comm. Mass Spectrom. 1991,5,101-105. 

Pyridine-d5 was found to show the most favorable solvent-induced changes of the chemical shifts for the three compounds in so far as a first-order analysis of the 60-MHz spectra was possible, the observed splittings gave no indication for solvent-induced, conformational changes. 

For reactions of bifunctional chains X—Y, two different types of solvent interactions are considered, i.e. (i) solvation of the non-reacting part of the molecule affecting the ease of cyclisation through solvent-induced conformational changes, and (ii) solvation of the reacting ends affecting the inherent reactivity of the ends themselves. 

B. Chain Conformation and Solvent-Induced Conformational Changes... 

Fig. 6. Solvent-induced conformational changes in peptide 7 [9]. The hydrophilic residues are in bold face. On the left, the tr-helix axial projection on the right, the 0-sheet side-view representation...

Perez S, Thnavel F, Vergelati C (1985) Experimental evidence of solvent-induced conformational changes in maltose. Nouv J Chim 9 561-564... 

J.A. Loo, R.R. Ogorzalek Loo, H.R. Udseth, C.G. Edmonds, R.D. Smith, Solvent-induced conformational changes of polypeptides probed by ESI-MS, Rapid Conunun. Mass Spectrom., 5 (1991) 101. 

The Xmax of the Trp fluorescence spectrum shifts to shorter wavelengths (blue shift) and the intensity of X ax increases as the polarity of the environment decreases. Otherwise Trp is internal in a nonpolar environment or the solvent induces conformational change that brings it to the surface. 

The presence of such a free Ser hydroxymethyl group as a component giving rise to rapidly relaxing species however, seems to be very important as a site for hydration in stabilizing the silk 1 form. In other words, a solvent-induced conformational change could be associated with the destabilization of the silk I or silk 1 type form as a result of dehydration. 

Evidence for solvent-induced conformational changes in methyl maltoside has been obtained from n.m.r. studies of the deuterated molecule. The observed values of three bond coupling constants for C(1)-H(4. ) and C(4 )-H(1) in deuterated DMSO and dioxan were... 

Vargas A, Bonalumi N, Ferri D, Baiker A (2006) Solvent-induced conformational changes of O-phenyl-cinchonidine a theoretical and VCD spectroscopy study. J Phys Chem A 110 1118-1127... 

Solvent-induced conformational changes may also affect the tendency to chain cyclization. Bruice and Turner(3) found that succinate esters have intramolecular rate constants about 20-fold smaller in water than the phthalate esters do, whereas the rate constants for the two groups of esters are essentially the same in 1 M H2O in DMSO. The observation was interpreted in terms of extended conformation of the succinate esters in water and predominant cisoid conformation in the H2O - DMSO mixed solvent. 

In conclusion, although solvent effects as intrinsically bound to the cyclization phenomenon are generally small, they can arise from a number of situations including desolvation of a bifunctional short chain, interdependence of solvation and steric strains in the transition state of medium-ring formation, steric inhibition of solvation in special reaction series, and solvent-induced conformational changes. Some of the effects require further investigation for a more quantitative assessment of the energetic factors involved. 

Ma SL, Shen S, Lee H, Yee N, Senanayake C, Nafie LA, Giinberg N (2008) Vibrational circular dichroism of amylose carbamate structure and solvent-induced conformational changes. Tetrahedron Asymmetry 19 2111-2114... 

The influence of solvent-induced conformational changes in PEO may be studied... 

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