Unknown

Dataset Information

0

G-protein from Medicago sativa: functional association to photoreceptors.


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.

SUBMITTER: Muschietti JP 

PROVIDER: S-EPMC1132536 | BioStudies | 1993-01-01

SECONDARY ACCESSION(S): 10.1042/bj2910383

REPOSITORIES: biostudies

Similar Datasets

1997-01-01 | S-EPMC1218427 | BioStudies
1989-01-01 | S-EPMC1133296 | BioStudies
1989-01-01 | S-EPMC1138752 | BioStudies
2009-01-01 | S-EPMC2753067 | BioStudies
1989-01-01 | S-EPMC1138665 | BioStudies
1988-01-01 | S-EPMC1149154 | BioStudies
1992-01-01 | S-EPMC1130790 | BioStudies
1991-01-01 | S-EPMC1151149 | BioStudies
2000-01-01 | S-EPMC1221010 | BioStudies
1990-01-01 | S-EPMC1131679 | BioStudies