Selective oxidation of methionine beta(55)D6 at the alpha 1 beta 1 interface in hemoglobin completely destabilizes the T-state.
J Biol Chem
; 264(30): 17745-9, 1989 Oct 25.
Article
em En
| MEDLINE
| ID: mdl-2808347
ABSTRACT
When methionine beta(55)D6 in human hemoglobin is oxidized to its sulfoxide derivative, the modified protein appears to maintain most of the chemical and structural properties typical of the native protein. On the contrary, the functional behavior is drastically changed, being characterized (like that of the isolated chains) by high oxygen affinity (p50 = 0.47 torr in 0.1 M Tris (pH 7.3) + 0.1 M NaCl at 25 degrees C), absence of cooperativity (n = 1), and lack of Bohr effect. The complete destabilization of the T-state as a result of this modification is related to a perturbation of the alpha 1 beta 1 subunit interface, which in native hemoglobin remains static during the quaternary ligand-linked transition. Results also suggest that methionyl sulfoxide-containing hemoglobin, obtained under different conditions, assumes functionally different R-states, none of which is exactly comparable with that typical of the native protein.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Compostos de Tosil
/
Hemoglobina A
/
Metionina
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
1989
Tipo de documento:
Article
País de afiliação:
Itália