Ornithine carbamoyltransferase folding/unfolding is a complex and not completely understood process. Our experimental results suggest that ornithine carbamoyltransferase interacts in a completely different way with urea and guanidine hydrochloride. In fact, we noticed that, increasing concentration from 0.0 to 8.0 M of the two additives, the enzyme follows a simple one-step transition mechanism in the presence of guanidine hydrochloride, with two macroscopic states (the native and the denatured one) significantly populated, whereas in the presence of urea a lot of different protein states can be detected and analyzed. Circular dichroism and UV-visible spectroscopy reveal a similar mechanism of perturbation at high temperature, with opening of hydrophobic core and a significant loss in α-helix structure in the presence of guanidine hydrochloride that cannot be found in the presence of urea.
Ornithine Carbamoyltransferase Unfolding States in the Presence of Urea and Guanidine Hydrochloride
BARRECA, Davide;LAGANA', Giuseppina;FICARRA, Silvana;TELLONE, Ester;LEUZZI, Ugo;GALTIERI, Antonio;BELLOCCO, Ersilia Santa
2014-01-01
Abstract
Ornithine carbamoyltransferase folding/unfolding is a complex and not completely understood process. Our experimental results suggest that ornithine carbamoyltransferase interacts in a completely different way with urea and guanidine hydrochloride. In fact, we noticed that, increasing concentration from 0.0 to 8.0 M of the two additives, the enzyme follows a simple one-step transition mechanism in the presence of guanidine hydrochloride, with two macroscopic states (the native and the denatured one) significantly populated, whereas in the presence of urea a lot of different protein states can be detected and analyzed. Circular dichroism and UV-visible spectroscopy reveal a similar mechanism of perturbation at high temperature, with opening of hydrophobic core and a significant loss in α-helix structure in the presence of guanidine hydrochloride that cannot be found in the presence of urea.Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.