2e7s
Crystal structure of the yeast Sec2p GEF domain
Structural highlights
FunctionSEC2_YEAST Guanine nucleotide exchange factor for SEC4, catalyzing the dissociation of GDP from SEC4 and also potently promoting binding of GTP. Activation of SEC4 by SEC2 is needed for the directed transport of vesicles to sites of exocytosis. Binds the Rab GTPase YPT32, but does not have exhange activity on YPT32.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedVesicular traffic during exocytosis is regulated by Rab GTPase, Sec4p in yeast, which is activated by a guanine nucleotide exchange factor (GEF) called Sec2p. The GEF activity is localized in the N-terminal 160 residues of Sec2p, which lacks sequence similarity with any other GEFs with known structures, and thereby the guanine nucleotide exchange mechanism by Sec2p remains unknown. Here, we report the crystal structure of the Sec2p GEF domain at 3.0 A resolution. The structure unexpectedly consists of a homodimeric, parallel coiled coil that extends over 180 A. Pull-down and guanine nucleotide exchange analyses on a series of deletion and point mutants of Sec2p unveiled the catalytic residues for its GEF activity as well as the Sec4p binding site, thus presenting a nucleotide exchange mechanism by a simple coiled coil. The present functional analyses allow us to build the Sec2p:Sec4p complex model, which explains the specificity for Rab GTPases by their respective GEF proteins. Asymmetric coiled-coil structure with Guanine nucleotide exchange activity.,Sato Y, Shirakawa R, Horiuchi H, Dohmae N, Fukai S, Nureki O Structure. 2007 Feb;15(2):245-52. PMID:17292842[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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