Abstract |
In mammals, G-protein alpha, beta, gamma polypeptides are encoded by at least 16, 4 and 7 genes, respectively. G alpha-subunits bind and hydrolyze GTP and have the sites for bacterial toxin-catalyzed ADP-ribosylation. A structural model of G alpha-subunits can be defined on the basis of similarities between G alpha and other members of the GTP-binding proteins. The resulting G alpha model specifies the spatial relationship among the guanine nucleotide binding site, the binding site of the G beta gamma-subunit complex, likely regions of effector and receptor interaction, and sites of cholera or pertussis toxin-induced modification. The architecture of the G alpha core is the same as that of p21ras. Experimental evidence from immunological, molecular genetic and biochemical studies support the G alpha model. The G alpha-subunits alone were previously thought to act on the effector enzymes; However, recent evidence indicates that the G beta gamma-dimer also plays an important part in effector activation.
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Authors | S Hoshino, T Katada |
Journal | Nihon yakurigaku zasshi. Folia pharmacologica Japonica
(Nihon Yakurigaku Zasshi)
Vol. 103
Issue 6
Pg. 249-62
(Jun 1994)
ISSN: 0015-5691 [Print] Japan |
PMID | 8039766
(Publication Type: English Abstract, Journal Article, Review)
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Chemical References |
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Topics |
- Amino Acid Sequence
- Animals
- Binding Sites
- GTP-Binding Proteins
(chemistry, physiology)
- Humans
- Molecular Sequence Data
- Protein Conformation
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