The crystal structure of rna1p: a new fold for a GTPase-activating protein.
rna1p is the Schizosaccharomyces pombe ortholog of the mammalian GTPase-activating protein (GAP) of Ran. Both proteins are essential for nuclear transport. Here, we report the crystal structure of rna1p at 2.66 A resolution. It contains 11 leucine-rich repeats that adopt the nonglobular shape of a crescent, bearing no resemblance to ... RhoGAP or RasGAP. The invariant residues of RanGAP form a contiguous surface, strongly indicating the Ran-binding interface. Alanine mutations identify Arg-74 as a critical residue for GTP hydrolysis. In contrast to RasGAP and RhoGAP, Arg-74 could be substituted by lysine and contributed significantly to the binding of Ran. Therefore, we suggest a GAP mechanism for rna1p, which constitutes a variation of the arginine finger mechanism found for Ras GAP and RhoGAP.
Mesh Terms:
Amino Acid Sequence, Amino Acid Substitution, Animals, Binding Sites, Conserved Sequence, Crystallography, X-Ray, Fungal Proteins, GTP-Binding Proteins, GTPase-Activating Proteins, Guanosine Triphosphate, Humans, Hydrolysis, Leucine, Models, Molecular, Molecular Sequence Data, Nuclear Proteins, Protein Binding, Protein Conformation, Protein Structure, Secondary, Proteins, Schizosaccharomyces, Schizosaccharomyces pombe Proteins, ran GTP-Binding Protein, ras GTPase-Activating Proteins
Amino Acid Sequence, Amino Acid Substitution, Animals, Binding Sites, Conserved Sequence, Crystallography, X-Ray, Fungal Proteins, GTP-Binding Proteins, GTPase-Activating Proteins, Guanosine Triphosphate, Humans, Hydrolysis, Leucine, Models, Molecular, Molecular Sequence Data, Nuclear Proteins, Protein Binding, Protein Conformation, Protein Structure, Secondary, Proteins, Schizosaccharomyces, Schizosaccharomyces pombe Proteins, ran GTP-Binding Protein, ras GTPase-Activating Proteins
Mol. Cell
Date: Jun. 01, 1999
PubMed ID: 10394366
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