G-protein from Medicago sativa: functional association to photoreceptors.
Biochem J
; 291 ( Pt 2): 383-8, 1993 Apr 15.
Article
em En
| MEDLINE
| ID: mdl-8484719
ABSTRACT
G-protein subunits were characterized from Medicago sativa (alfalfa) seedlings. Crude membranes and GTP-Sepharose-purified fractions were electrophoresed on SDS/polyacrylamide gels and analysed by Western blotting with 9193 (anti-alpha common) and AS/7 (anti-alpha t, anti-alpha i1 and anti-alpha i2) polyclonal antibodies. These procedures led to the identification of a specific polypeptide band of about 43 kDa. Another polypeptide reacting with the SW/1 (anti-beta) antibody, of about 37 kDa, was also detected. The 43 kDa polypeptide bound specifically [alpha-32P]GTP by a photoaffinity reaction and was ADP-ribosylated by activated cholera toxin, but not by pertussis toxin. Irradiation of etiolated Medicago sativa protoplast preparations at 660 nm for 1 min produced a maximal increase in the guanosine 5'-[gamma-thio]triphosphate (GTP[35S])-binding rate. After this period of irradiation, the binding rate tended to decrease. The effect of a red-light (660 nm) pulse on the binding rate was reversed when it was immediately followed by a period of far-red (> 730 nm) illumination. These results may suggest that activation of GTP[S]-binding rate was a consequence of conversion of phytochrome Pr into the Ptr form.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Células Fotorreceptoras
/
Proteínas de Ligação ao GTP
/
Medicago sativa
Tipo de estudo:
Risk_factors_studies
Idioma:
En
Revista:
Biochem J
Ano de publicação:
1993
Tipo de documento:
Article
País de afiliação:
Argentina