Fig. 7.
A conserved arginine residue in the first homology box of GAP domains in all members of the Rho-GAP family and also GTPase-stimulating activity of the wild-type hMgcRacGAP and the mutant R385A*MgcRacGAP.
(A) Homology between members of RhoGAP family is shown. Sequence alignments were performed on the original GenBank entries for the indicated proteins using the Clustal algorithm of the DNA Star program. ABR indicates Bcr-related gene product. (B) The GTP-hydrolyzing activity of several recombinant GTPases was measured in the presence or absence of recombinant GAP domain of the wild-type hMgcRacGAP or the mutant R385A*MgcRacGAP. The amount of [γ-32P] GTP remaining bound to GTPases after 3 minutes was determined by a filter-binding assay and expressed as a percentage of the initial amount of GTP bound to each protein. The results shown are the averages ± SD of 3 independent experiments.