4KAX image
Entry Detail
PDB ID:
4KAX
Title:
Crystal structure of the Grp1 PH domain in complex with Arf6-GTP
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2013-04-23
Release Date:
2013-08-14
Method Details:
Experimental Method:
Resolution:
1.85 Å
R-Value Free:
0.23
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
P 43 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:ADP-ribosylation factor 6
Mutations:Q67L
Chain IDs:A
Chain Length:169
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Cytohesin-3
Chain IDs:B
Chain Length:161
Number of Molecules:1
Biological Source:Homo sapiens
Primary Citation
Structural basis for membrane recruitment and allosteric activation of cytohesin family Arf GTPase exchange factors.
Proc.Natl.Acad.Sci.USA 110 14213 14218 (2013)
PMID: 23940353 DOI: 10.1073/pnas.1301883110

Abstact

Membrane recruitment of cytohesin family Arf guanine nucleotide exchange factors depends on interactions with phosphoinositides and active Arf GTPases that, in turn, relieve autoinhibition of the catalytic Sec7 domain through an unknown structural mechanism. Here, we show that Arf6-GTP relieves autoinhibition by binding to an allosteric site that includes the autoinhibitory elements in addition to the PH domain. The crystal structure of a cytohesin-3 construct encompassing the allosteric site in complex with the head group of phosphatidyl inositol 3,4,5-trisphosphate and N-terminally truncated Arf6-GTP reveals a large conformational rearrangement, whereby autoinhibition can be relieved by competitive sequestration of the autoinhibitory elements in grooves at the Arf6/PH domain interface. Disposition of the known membrane targeting determinants on a common surface is compatible with multivalent membrane docking and subsequent activation of Arf substrates, suggesting a plausible model through which membrane recruitment and allosteric activation could be structurally integrated.

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