Guanine nucleotide exchange factor for Ras-like GTPases; N-terminal motif
SMART accession number:SM00229
Description: A subset of guanine nucleotide exchange factor for Ras-like small GTPases appear to possess this domain N-terminal to the RasGef (Cdc25-like) domain. The recent crystal structureof Sos shows that this domain is alpha-helical and plays a "purely structural role" (Nature 394, 337-343).
Interpro abstract (IPR000651):

The crystal structure of the guanine nucleotide exchange factor (GEF) region of human Sos1 complexes with Ras has been solved [(PUBMED:9690470)]. The structure consists of two distinct alpha helical structural domains: the N-terminal domain which seems to have a purely structural role and the C-terminal domain which is sufficient for catalytic activity and contains all residues that interact with Ras. A main feature of the catalytic domain is the protrusion of a helical hairpin important for the nucleotide-exchange mechanism. The N-terminal domain is likely to be important for the stability and correct placement of the hairpin structure.

This entry represents a domain found in several GEF for Ras-like small GTPases which lies N-terminal to the RasGef (Cdc25-like) domain.

Family alignment:
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There are 4059 RasGEFN domains in 3803 proteins in SMART's nrdb database.

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