1uad: Difference between revisions

Revision as of 10:57, 3 May 2008

Crystal structure of the RalA-GppNHp-Sec5 Ral-binding domain complex

OverviewOverview

The sec6/8 complex or exocyst is an octameric protein complex that functions during cell polarization by regulating the site of exocytic vesicle docking to the plasma membrane, in concert with small GTP-binding proteins. The Sec5 subunit of the mammalian sec6/8 complex binds Ral in a GTP-dependent manner. Here we report the crystal structure of the complex between the Ral-binding domain of Sec5 and RalA bound to a non-hydrolyzable GTP analog (GppNHp) at 2.1 A resolution, providing the first structural insights into the mechanism and specificity of sec6/8 regulation. The Sec5 Ral-binding domain folds into an immunoglobulin-like beta-sandwich structure, which represents a novel fold for an effector of a GTP-binding protein. The interface between the two proteins involves a continuous antiparallel beta-sheet, similar to that found in other effector/G-protein complexes, such as Ras and Rap1A. Specific interactions unique to the RalA.Sec5 complex include Sec5 Thr11 and Arg27, and RalA Glu38, which we show are required for complex formation by isothermal titration calorimetry. Comparison of the structures of GppNHp- and GDP-bound RalA suggests a nucleotide-dependent switch mechanism for Sec5 binding.

About this StructureAbout this Structure

1UAD is a Protein complex structure of sequences from Homo sapiens and Rattus norvegicus. Full crystallographic information is available from OCA.

ReferenceReference

Structural basis of the interaction between RalA and Sec5, a subunit of the sec6/8 complex., Fukai S, Matern HT, Jagath JR, Scheller RH, Brunger AT, EMBO J. 2003 Jul 1;22(13):3267-78. PMID:12839989 Page seeded by OCA on Sat May 3 10:57:53 2008

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OCA

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 [[Image:1uad.jpg|left|200px]]
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-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1uad FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1uad OCA], [http://www.ebi.ac.uk/pdbsum/1uad PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1uad RCSB]</span>
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 '''Crystal structure of the RalA-GppNHp-Sec5 Ral-binding domain complex'''
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 [[Category: Matern, H T.]]
 [[Category: Scheller, R H.]]
-[[Category: beta-sandwich]]
+[[Category: Beta-sandwich]]
-[[Category: immunogloblin-like fold]]
+[[Category: Immunogloblin-like fold]]
-[[Category: small gtp-binding protein]]
+[[Category: Small gtp-binding protein]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 10:57:53 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 00:07:34 2008''