A differential scanning calorimetric study of the thermal unfolding of apo- and holo-cytochrome b562.
Protein Sci
; 7(4): 961-5, 1998 Apr.
Article
em En
| MEDLINE
| ID: mdl-9568902
ABSTRACT
Cytochrome b562 is a four-helix-bundle protein containing a non-covalently bound b-type heme prosthetic group. In the absence of heme, cytochrome b562 remains highly structured under native conditions. Here we report thermodynamic data for the thermal denaturation of the holo- and apoproteins as determined by differential scanning calorimetry. Thermal denaturation of holocytochrome b562 is a highly reversible process, and unexpectedly does not involve dissociation of the heme prosthetic group. Thermal denaturation of the corresponding apoprotein, with the heme group chemically removed, remains a cooperative, reversible process. Apocytochrome b562 is substantially destabilized relative to the holoprotein the t1/2 is more than ten degrees lower, and enthalpy and heat capacity changes are about one-half of the holoprotein values. However, the energetic parameters of apocytochrome b562 denaturation are within the range of observed values for small proteins.
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
3_ND
Base de dados:
MEDLINE
Assunto principal:
Dobramento de Proteína
/
Grupo dos Citocromos b
/
Proteínas de Escherichia coli
/
Escherichia coli
Idioma:
En
Revista:
Protein Sci
Ano de publicação:
1998
Tipo de documento:
Article