Effect of hexane on secondary structures of araujiain as observed by infrared spectroscopy.

EVELINA QUIROGA; GERARDO CAMÍ; NORA PRIOLO; SONIA BARBERIS.

San Carlos de Bariloche, Argentina

Congreso; XXXIX Encuentro Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2003

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.

The object of this work was to study the effect of hexane in a biphasic system on the secondary structure of the araujiain hI, by means of FTIR studies. These results were compare with those happened in Tris-HCl buffer pH 8.   According to FTIR studies was clear that the noncovalent forces, which maintain the secondary and tertiary structures of enzymes, were modified as a result of addition of the hexane to an aqueous enzyme solution. In the second-derivative analysis of the original spectrum, araujiain hI showed a stronger b-sheet band, a more random character and a greater a-helical character in buffer than in hexane-buffer. Larger amount of antiparallel b-sheet residues indicates the formation of tighter intermolecular hydrogen bond and enzymatic aggregate in buffer than in hexane-buffer. Then, araujiain hI in hexane-buffer is more flexible than in buffer. By other hand, the conformational differences of enzyme between both media were too readily detectable and they resulted in a native-like conformation