Heat-induced changes in the conformation of α- and β-crystalline: Unique thermal stability of α-crystallin

AbstractOf the crystallin proteins of the lens, the principal subunit of the β-crystallin, βB2 (βBp), has been considered to be the only heat-stable protein because it does not precipitate upon heating. In our recent investigations, however, we have found that the α-crystallin from bovine lenses is not only heat stable but also does not denature at temperatures up to 100°C. Using circular dichroism and fluorescence to monitor the conformational changes of α- and βB2-crystallins upon heating, we found that α-crystallin maintains a high degree of structure, whereas the βB2-crystallin shows a reversible sigmoidal order-disorder transition at about 58°C

Vibrational structure of molecular charge transfer bands in hydrocarbon-tetrahalo p-benzoquinone complexes

This article does not have an abstract

Spectrometric investigation of π=hydrogen bond formation between aromatic hydrocarbons and aromatic amines

The spectral shift in the longest wave length absorption band of naphthyl amine in going from a cyclohexane to a benzene, toluene or xylene solution has been associated with the hydrogen bond formation between the amino hydrogen of naphthyl amine and the π-electron system of aromatic hydro-carbons. The equilibrium constant for hydrogen bond formation was found to run parallel to the base strength of the π-electron system

Vibrational structure of molecular charge transfer bands, part. I. hydrocarbon-tetrahalo p-benzoquinone complexes in solution

Under high resolution the electronic charge transfer band of hydrocarbon-tetrahalo p-benzoquinone complexes in chloroform have been found to show vibrational structure of very low frequency of 150-250 cm-1. This has been associated with the change in donor-acceptor bond. The force constant of the intermolecular bond lies in the range1,35-1,70 X 105 dynes/cmfor a series of complexes

N° 94. — Crystal spectra of anthracene and pyrene complexes of tetra-halo p-benzoquinone

The sepctra of molecular complexes of anthracene and pyrene with tetrahalo p-benzoquinone in the crystalline state have been measured. The general feature of the absorption curve with respect to energy and the slate of polarization of the charge transfer band may be interpreted qualitatively in terms of « Crystals shift » and « Crystal Splitting » effects discussed by Davydov