G-protein from Medicago sativa: Functional association to photoreceptors

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-α(common)) and AS/7 (anti-α(t), anti-α(i1) and anti α(i2)) polyclonal...

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Publicado: 1993
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Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02646021_v291_n2_p383_Muschietti
http://hdl.handle.net/20.500.12110/paper_02646021_v291_n2_p383_Muschietti
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spelling paper:paper_02646021_v291_n2_p383_Muschietti2023-06-08T15:23:08Z G-protein from Medicago sativa: Functional association to photoreceptors cholera toxin guanine nucleotide binding protein guanosine 5' o (3 thiotriphosphate) pertussis toxin polyclonal antibody adenosine diphosphate ribosylation alfalfa article illumination immunoblotting irradiation molecular weight nonhuman photoaffinity labeling photoreceptor plant seed polyacrylamide gel electrophoresis priority journal protein binding protein purification protoplast Medicago sativa 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-α(common)) and AS/7 (anti-α(t), anti-α(i1) and anti α(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-β) antibody, of about 37 kDa, was also detected. The 43 kDa polypeptide bound specifically [α-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'-[γ-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 P(r) into the P(f)r form. 1993 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02646021_v291_n2_p383_Muschietti http://hdl.handle.net/20.500.12110/paper_02646021_v291_n2_p383_Muschietti
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic cholera toxin
guanine nucleotide binding protein
guanosine 5' o (3 thiotriphosphate)
pertussis toxin
polyclonal antibody
adenosine diphosphate ribosylation
alfalfa
article
illumination
immunoblotting
irradiation
molecular weight
nonhuman
photoaffinity labeling
photoreceptor
plant seed
polyacrylamide gel electrophoresis
priority journal
protein binding
protein purification
protoplast
Medicago sativa
spellingShingle cholera toxin
guanine nucleotide binding protein
guanosine 5' o (3 thiotriphosphate)
pertussis toxin
polyclonal antibody
adenosine diphosphate ribosylation
alfalfa
article
illumination
immunoblotting
irradiation
molecular weight
nonhuman
photoaffinity labeling
photoreceptor
plant seed
polyacrylamide gel electrophoresis
priority journal
protein binding
protein purification
protoplast
Medicago sativa
G-protein from Medicago sativa: Functional association to photoreceptors
topic_facet cholera toxin
guanine nucleotide binding protein
guanosine 5' o (3 thiotriphosphate)
pertussis toxin
polyclonal antibody
adenosine diphosphate ribosylation
alfalfa
article
illumination
immunoblotting
irradiation
molecular weight
nonhuman
photoaffinity labeling
photoreceptor
plant seed
polyacrylamide gel electrophoresis
priority journal
protein binding
protein purification
protoplast
Medicago sativa
description 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-α(common)) and AS/7 (anti-α(t), anti-α(i1) and anti α(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-β) antibody, of about 37 kDa, was also detected. The 43 kDa polypeptide bound specifically [α-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'-[γ-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 P(r) into the P(f)r form.
title G-protein from Medicago sativa: Functional association to photoreceptors
title_short G-protein from Medicago sativa: Functional association to photoreceptors
title_full G-protein from Medicago sativa: Functional association to photoreceptors
title_fullStr G-protein from Medicago sativa: Functional association to photoreceptors
title_full_unstemmed G-protein from Medicago sativa: Functional association to photoreceptors
title_sort g-protein from medicago sativa: functional association to photoreceptors
publishDate 1993
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02646021_v291_n2_p383_Muschietti
http://hdl.handle.net/20.500.12110/paper_02646021_v291_n2_p383_Muschietti
_version_ 1768546157661782016