We studied the temperature- and denaturant-induced denaturation of two thermophilic esterases, AFEST from Archeoglobus fulgidus and EST2 from Alicyclobacillus acidocaldarius, by means of circular dichroism measurements. Both enzymes showed a very high denaturation temperature: 99 °C for AFEST and 91 °C for EST2. They also showed a remarkable resistance against urea; at half-completion of the transition the urea concentration was 7.1 M for AFEST and 5.9 M for EST2. On the contrary, both enzymes showed a weak resistance against GuHCl; at half-completion of the transition the GuHCl concentration was 2.0 M for AFEST and 1.9 M for EST2. The thermodynamic parameters characterizing urea- and GuHCl-induced denaturation of the studied enzymes have been obtained by both the linear extrapolation model and the denaturant binding model. The dependence of the thermal stability on NaCl concentration for both esterases has also been determined. A careful analysis of the data, coupled with available structural information, has allowed the proposal of a reliable interpretation.
Temperature- and denaturant-induced unfolding of two thermophilic esterases / DEL VECCHIO, POMPEA GIUSEPPINA GRAZIA; G., Graziano; V., Granata; Barone, Guido; L., Mandrich; G., Manco; M., Rossi. - In: BIOCHEMISTRY. - ISSN 0006-2960. - STAMPA. - 41:4(2002), pp. 1364-1371. [10.1021/bi011146t]
Temperature- and denaturant-induced unfolding of two thermophilic esterases.
DEL VECCHIO, POMPEA GIUSEPPINA GRAZIA;BARONE, GUIDO;
2002
Abstract
We studied the temperature- and denaturant-induced denaturation of two thermophilic esterases, AFEST from Archeoglobus fulgidus and EST2 from Alicyclobacillus acidocaldarius, by means of circular dichroism measurements. Both enzymes showed a very high denaturation temperature: 99 °C for AFEST and 91 °C for EST2. They also showed a remarkable resistance against urea; at half-completion of the transition the urea concentration was 7.1 M for AFEST and 5.9 M for EST2. On the contrary, both enzymes showed a weak resistance against GuHCl; at half-completion of the transition the GuHCl concentration was 2.0 M for AFEST and 1.9 M for EST2. The thermodynamic parameters characterizing urea- and GuHCl-induced denaturation of the studied enzymes have been obtained by both the linear extrapolation model and the denaturant binding model. The dependence of the thermal stability on NaCl concentration for both esterases has also been determined. A careful analysis of the data, coupled with available structural information, has allowed the proposal of a reliable interpretation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
