The biosynthesis of nitrogenase MoFe protein polypeptides in free-living cultures of Rhizobium japonicum.
Biochim Biophys Acta
; 565(2): 365-78, 1979 Dec 17.
Article
em En
| MEDLINE
| ID: mdl-518887
ABSTRACT
The biosynthesis of the constituent polypeptides of nitrogenase component I (Rj 1) in free-living cultures of Rhizobium japonicum (strain 110) was investigated under different growth conditions. Cells were pulse-labelled and the proteins analysed by one and two-dimensional gel electrophoresis. The positions of the constituent Rj 1 polypeptides were identified by co-electrophoresis with purified Rj 1 isolated from bacteroids of soybean nodules, and by comparison with an immunoprecipitate from a culture induced for nitrogenase. The synthesis of the proteins preceded any detectable enzyme activity and increased with time, reaching a maximum after 3 days. At this time, between 6 and 8% of the total sodium dodecyl sulfate-soluble protein synthesized was Rj 1. Exposure to air led to a dramatic decrease in the rate of Rj 1 synthesis, with almost complete regression after 20 min. In the presence of KNO3, there was no nitrogenase activity, but the proteins were present in similar amounts (7%) as the control culture. When mannitol and glycerol were used as the sole carbon sources, the amount of Rj 1 synthesized was extremely low.
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Base de dados:
MEDLINE
Assunto principal:
Biossíntese Peptídica
/
Rhizobium
/
Nitrogenase
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1979
Tipo de documento:
Article