New wedge-shaped thermotropic liquid crystalline materials containing a guanidinium moiety at the apex organize into various supramolecular structures such as hexagonal columnar, rectangular columnar and Pm3n cubic mesophases depending on anions illustrating guest-directed self-organization in mesophases.

In the title compound, C(18)H(29)N(3)O, a polysubstituted guanidine, the torsion angles indicate that the guanidine unit and the carbonyl group are almost perpendicular to one another [O-C-N-C= -7.40 (18), C-N-C-N= -97.21 (15) and 86.41 (13)°]. The crystal packing is stablized by inter-molecular N-H⋯O hydrogen bonds, which link the mol-ecules into a chain.

We investigate the equilibrium unfolding of Zn-cytochrome c in guanidine hydrochloride by three-pulse photon echo peak shift (3PEPS) spectroscopy. Unexpectedly, the measurements reveal that inhomogeneous broadening of the sample at the midpoint of the denaturation is larger than that of either native or unfolded states. To interpret this finding, we present simulations of the peak shift for bot...

We found, by circular dichroism and Raman spectroscopy measurements, that the secondary structure of the native ovalbumin and of its heat-stable form, called S-ovalbumin, is a probe of the structural differences between the two proteins. Small angle X-ray scattering and circular dichroism measurements performed on the two proteins under denaturing conditions, with different concentrations of gu...

Comparative analysis of conformational stabilities was performed for two widely used genetic reporters, EGFP and DsRed, proteins exhibiting similar beta-can folds, but possessing different oligomeric organization and chromophore structures. Two factors affecting protein stability in vitro, such as elevated temperatures and a chaotropic agent guanidine hydrochloride, were studied. In vivo tolera...

Inactivation of purified β-Galactosidase was done with GdnHCl in the absence and presence of varying [galactose] at 50°C and at pH 4.5. Lineweaver-Burk plots of initial velocity data, in the presence and absence of guanidine hydrochloride (GdnHCl) and galactose, were used to determine the relevant K(m) and V(max) values, with p-nitrophenyl β-D-galactopyranoside (pNPG) as substrate, S. Plots of ...

A number of very careful studies have been made in recent years of the thermal transitions which small globular proteins undergo at low pH. These transitions reflect the destruction of the ordered conformation of the native protein, and the products of the transition have the properties of highly disordered polypeptide chains. The principal objective of such studies has, however, been to determ...

In a previous communication, it was shown that on prolonged exposure to urea at temperatures above 20” pepsin is irreversibly inactivated (1). The loss of activity is most marked in the pH range of 4.6 to 5.6 and is always accompanied by the formation of nonprotein material that originates from autodigestion of the protein. Since urea is known to affect the secondary structure of proteins by ru...

The kinetics of actin unfolding induced by guanidine hydrochloride of different concentrations was studied. The parametric representation of the kinetic dependencies of tryptophan fluorescence intensity changes recorded at two wavelengths allowed us to detect and characterize a new essentially unfolded kinetic intermediate. Its characteristics suggested that this intermediate state is a premolt...