Ethylene glycol, conformational studies

The conformation of ethylene glycol occluded in high silica sodalite has been determined [25]. In the category of zeolite-hydrocarbon complexes, we have seen completion of studies at relatively low loading levels of benzene in zeolites L [26,27] and Na-Y [28]. Benzene has also been studied in... 

The nucleation of parallel (3-sheet structure via metal ion chelation in aqueous solution was investigated by incorporating an ethylene glycol spacer between a dibenzofuran-4,6-dipro-panoic acid template and the two peptide strands (Scheme 6).[7 The flexibility of the ethylene glycol spacer allows the peptide to sample a variety of largely unordered conformations in the absence of metal ions. Upon binding of palladium(II), nickel(II), or copper(II) ions, the peptidomimetic adopts a well-defined (3-sheet conformation as discerned from biophysical and spectroscopic studies (i.e., CD, IR absorption, and H NMR spectrometry).17 The synthesis of the dibenzofuran-4,6-dipropanoic acid template was discussed... 

A solvent which has been foimd to be of great interest in connection with protein conformation studies is ethylene glycol. Sage and Singer (1958, 1962) have investigated in some detail the properties of RNase in pure ethylene glycol, containing added neutral electrolyte. They examined the ultraviolet absorption spectrum, the ionization behavior of the tyrosine residues by spectrophotometric titration experiments, and the optical rotatory dispersion of the system. 

Peptides are usually less adversely affected by non-aqueous conditions than proteins. The conformation of somatostatin (pH 1.25) has been characterized by NMR in water, DMSO, MeOH and ethylene glycol (Verheyden et al., 1990 Verheyden et al., 1991 Jackson and Mantsch, 1992b Verheyden et al., 1994b). In all of the solvent conditions, the secondary structure was conserved, and was characterized to be a (3-sheet structure with a (3-turn. Further studies indicated that as the viscosity of the solvent system increased, the conformational flexibility decreased, stabilizing the structure. Gonversely, signihcant changes in the... 

Verheyden P, De Wolf E, Jaspers H, and Van Binst G. Comparing Conformations at Low Temperature and at High Viscosity. Conformational Study of Somatostatin and Two of its Analogues in Methanol and in Ethylene Glycol. Int J Peptide Protein Res 1994b 44 401—409. 

Blumenfeld, L.A., R.M. Davydov, S.M. Magonov, and R.O. Vilu (1974). Studies on the conformational changes of metalloproteins induced by electrons in water-ethylene glycol solutions at low temperatures. Haemoglobin. FEBS Lett. 49, 246-248. 

Jeong et al. studied the gelation behavior of poly(ethylene glycol)-h-poly(L-alanine) (PEG-h-L-PA) block copolymers in water [117, 118]. They suggested that the P-sheet structure of l-PA plays a critical role in developing a fibrous nanostructure as well as in the sol-to-gel transition of the copolymer solutions (Fig. 14). The conformation of l-PA in water is random coil at low concentrations. As the concentration increases, block copolymers start to aggregate and the conformation... 

---