Disulfide-linked bovine beta-lactoglobulin dimers fold slowly, navigating a glassy folding landscape.
Biochemistry
; 47(22): 5996-6006, 2008 Jun 03.
Article
en En
| MEDLINE
| ID: mdl-18465840
ABSTRACT
To gain insight into the folding of large proteins, we constructed a bovine beta-lactoglobulin (beta-lg) dimeric mutant, A34C/C121A beta-lg. In the mutant, a free thiol group of wild-type beta-lg at Cys121 was removed and two beta-lg molecules were linked by a disulfide bridge through Cys34 created at the dimer's interface. Under strongly native conditions at low concentrations of urea, the refolding yield of A34C/C121A beta-lg was low when monitored by heteronuclear NMR spectroscopy. However, under marginally native conditions, the yield improved notably, although the refolding was still slow. H-D exchange pulse labeling monitored using heteronuclear NMR spectroscopy indicated that A34C/C121A beta-lg forms a folding intermediate similar to monomeric C121A beta-lg in spite of its slow folding. These results indicate that the rapid formation of folding intermediates driven by local interactions occurs in a manner independent of the molecular size and that, if the non-native interactions are too strong, the kinetic trap is set, leading to a glasslike misfolded state. The results suggest the important roles of marginal stability and pathways in making the folding of large proteins possible.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Disulfuros
/
Lactoglobulinas
Límite:
Animals
Idioma:
En
Año:
2008
Tipo del documento:
Article