Partially folded intermediates during trypsinogen denaturation
Braz. j. med. biol. res
; 32(6): 673-82, Jun. 1999. graf
Article
en En
| LILACS
| ID: lil-233699
Biblioteca responsable:
BR1.1
RESUMO
The equilibrium unfolding of bovine trypsinogen was studied by circular dichroism, differential spectra and size exclusion HPLC. The change in free energy of denaturation was delta GH2O = 6.99 + ou - 1.40 kcal/mol for guanidine hydrochloride and delta GH2O = 6.37 + ou - 0.57 kcal/mol for urea. Satisfactory fits of equilibrium unfolding transitions required a three-state model involving an intermediate in addition to the native and unfolded forms. Size exclusion HPLC allowed the detection of an intermediate population of trypsinogen whose Stokes radii varied from 24.1 + ou - 0.4 angstron to 26.0 + ou - 0.3 angstron 1.5 M and 2.5 M guanidine hydrochloride, respectively. During urea denaturation, the range of Stokes radii varied from 23.9 + ou - 0.3 angstron to 25.7 + ou - 0.6 angstron for 4.0 M and 6.0 M urea, respectively. Maximal intrinsic fluorescence was observed at about 3.8 M urea with 8-aniline-1-naphthalene sulfonate (ANS) binding. These experimental data indicate that the unfolding of bovine trypsinogen is not a simple transition and suggest that the equilibrium intermediate population comprises one intermediate that may be characterized as a molten globule. To obtain further insight by studying intermediates representing different stages of unfolding, we hope to gain a better understanding of the complex interrelations between protein conformation and energetics.
Texto completo:
1
Colección:
01-internacional
Base de datos:
LILACS
Asunto principal:
Tripsinógeno
/
Pliegue de Proteína
Límite:
Animals
Idioma:
En
Revista:
Braz. j. med. biol. res
Asunto de la revista:
BIOLOGIA
/
MEDICINA
Año:
1999
Tipo del documento:
Article