Fig. 6
From: New insights into the molecular mechanism of the Rab GTPase Sec4p activation
Sec2p truncations affecting nucleotide dissociation activity. MantGDP dissociation from Sec4p was measured by reduction in fluorescence intensity after mixing excess of unlabeled GDP (300 μM) plus: buffer (black) or 500nM of different truncations of Sec2p (a). Analysis of how mutations on amino acid region 142–160 of Sec2p affect the stimulation of nucleotide dissociation of Sec4p are shown on (b). All assays were done using 1 μM Sec4p19–187 preloaded with mantGDP. The superposition between the complexes Sec4p.GDP.Sec2p and Sec4p.Sec2p is shown on (c). Regions of Sec2p that were truncated for the crystallization of Sec4p.GDP.Sec2p complex are colored in brown in the Sec2p structure of the complex Sec4p.Sec2p (reference). Leucine residues suggested to be important for the GEF activity of Sec2p are labeled