Temperature-induced states of isolated F1-ATPase affect catalysis, enzyme conformation and high-affinity nucleotide binding sites.
Biochim Biophys Acta
; 976(1): 77-84, 1989 Aug 17.
Article
en En
| MEDLINE
| ID: mdl-2527562
ABSTRACT
Isolated, nucleotide-depleted bovine-heart F1-ATPase exhibits a break in Arrhenius plot with a 2.7-fold increase in activation energy of ATP hydrolysis below 18-19 degrees C. Analysis of intrinsic tyrosine fluorescence and of the circular dichroism of F1-ATPase showed an abrupt and reversible conformational change occurring at the break temperature, characteristic of a structural tightening at low temperature. Analysis of catalytic nucleotide binding sites using fluorescent ADP analog, 3'-O-(1-naphthoyl)adenosine diphosphate did not show any significant change in affinity of nucleotide binding around the transition temperature but the bound fluorophore exerted a more restricted motion and slower rotation at temperature below the break, indicating a change in the mobility of groups in the close neighbourhood. It is concluded that, as a result of temperature, two kinetically distinct states of F1-ATPase are induced, due to a change in enzyme conformation, which influences directly the properties of catalytic nucleotide binding sites.
Buscar en Google
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
ATPasas de Translocación de Protón
/
Mitocondrias Cardíacas
/
Nucleótidos
Límite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
1989
Tipo del documento:
Article
País de afiliación:
Italia