Abstract
Three residues of human ADP-ribosylation factor 3 (ARF3) (F51, W66 and Y81) cluster into a hydrophobic pocket in the inactive, GDP-bound protein. Disruption of the hydrophobic pocket with mutations at these residues increased the rate of GDP dissociation and association, but not always that of GTPgammaS. Several of the same mutants were found to be defective, often selectively, in binding different ARF effectors in two-hybrid assays. These results highlight three features of these hydrophobic residues in regulating (1) the rate of GDP dissociation, (2) the conformational changes that promote GTP binding and (3) their role in binding target proteins.
MeSH terms
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ADP-Ribosylation Factor 1 / chemistry*
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ADP-Ribosylation Factor 1 / metabolism
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ADP-Ribosylation Factors / chemistry*
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ADP-Ribosylation Factors / metabolism*
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Amino Acid Substitution
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Binding Sites
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Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
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Guanosine Diphosphate / chemistry
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Guanosine Diphosphate / metabolism*
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Humans
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Kinetics
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Models, Molecular
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Mutagenesis, Site-Directed
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Protein Conformation
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Protein Structure, Secondary
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
Substances
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Recombinant Proteins
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Guanosine Diphosphate
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Guanosine 5'-O-(3-Thiotriphosphate)
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ARF3 protein, human
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ADP-Ribosylation Factor 1
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ADP-Ribosylation Factors