3n5c
Crystal Structure of Arf6DELTA13 complexed with GDP
Structural highlights
FunctionARF6_HUMAN GTP-binding protein involved in protein trafficking; regulates endocytic recycling and cytoskeleton remodeling. May modulate vesicle budding and uncoating within the Golgi apparatus. Functions as an allosteric activator of the cholera toxin catalytic subunit, an ADP-ribosyltransferase. Involved in the regulation of dendritic spine development (By similarity). Contributes to the regulation of dendritic branching and filopodia extension.[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 PubMedThe small GTPases Arf1 and Arf6 have nonoverlapping functions in cellular traffic despite their very high sequence and structural resemblance. Notably, the exquisite isoform specificity of their guanine nucleotide exchange factors and their distinctive sensitivity to the drug brefeldin A cannot be explained by any straightforward structural model. Here we integrated structural and spectroscopic methods to address this issue using Delta13Arf6-GDP, a truncated mutant that mimics membrane-bound Arf6-GDP. The crystal structure of Delta13Arf6-GDP reveals an unprecedented unfolding of the GTPase core beta-strands, which is fully accounted for by small-angle X-ray scattering data in solution and by ab initio three-dimensional envelope calculation. NMR chemical shifts identify this structural disorder in Delta13Arf6-GDP, but not in the closely related Delta17Arf1-GDP, which is consistent with their comparative thermodynamic and hydrodynamic analyses. Taken together, these experiments suggest an unfolding model for the nucleotide switch of Arf6 and shed new light on its biochemical differences with Arf1. SAXS and X-ray crystallography suggest an unfolding model for the GDP/GTP conformational switch of the small GTPase Arf6.,Biou V, Aizel K, Roblin P, Thureau A, Jacquet E, Hansson S, Guibert B, Guittet E, van Heijenoort C, Zeghouf M, Perez J, Cherfils J J Mol Biol. 2010 Oct 1;402(4):696-707. Epub 2010 Aug 13. PMID:20709080[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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