Enhanced CO2/O2 specificity of a site-directed mutant of ribulose-bisphosphate carboxylase/oxygenase.
J Biol Chem
; 267(10): 6475-8, 1992 Apr 05.
Article
em En
| MEDLINE
| ID: mdl-1551863
ABSTRACT
The CO2/O2 specificity factor of ribulose-bisphosphate carboxylase/oxygenase partially determines the efficiency of photosynthetic carbon assimilation. Heretofore, engineered alterations of the enzyme have only decreased the selectivity for CO2 utilization. We show that alanyl replacement of active-site Ser-368 of the Rhodospirillum rubrum carboxylase enhances the carboxylation selectivity approximately 1.6-fold over the wild-type level. This enhancement reflects a greater relative decline in oxygenase efficiency than in carboxylase efficiency. In contrast to wild-type enzyme, the carboxylase activity of the Ser-368 mutant protein is not perceptibly inhibited by O2, perhaps indicative of a change in rate-limiting steps in the overall reaction pathway.
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Base de dados:
MEDLINE
Assunto principal:
Oxigênio
/
Ribulose-Bifosfato Carboxilase
/
Dióxido de Carbono
Idioma:
En
Ano de publicação:
1992
Tipo de documento:
Article