2A5G: Cholera Toxin A1 Subunit Bound To Arf6(Q67l)

The Vibrio cholerae bacterium causes devastating diarrhea when it infects the human intestine. The key event is adenosine diphosphate (ADP)-ribosylation of the human signaling protein GSalpha, catalyzed by the cholera toxin A1 subunit (CTA1). This reaction is allosterically activated by human ADP-ribosylation factors (ARFs), a family of essential and ubiquitous G proteins. Crystal structures of a CTA1:ARF6-GTP (guanosine triphosphate) complex reveal that binding of the human activator elicits dramatic changes in CTA1 loop regions that allow nicotinamide adenine dinucleotide (NAD+) to bind to the active site. The extensive toxin:ARF-GTP interface surface mimics ARF-GTP recognition of normal cellular protein partners, which suggests that the toxin has evolved to exploit promiscuous binding properties of ARFs.
PDB ID: 2A5GDownload
MMDB ID: 34802
PDB Deposition Date: 2005/6/30
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.66  Å
Source Organism:
Homo sapiens
Similar Structures:
Biological Unit for 2A5G: dimeric; determined by author and by software (PISA)
Molecular Components in 2A5G
Label Count Molecule
Proteins (2 molecules)
Adp-ribosylation Factor 6(Gene symbol: ARF6)
Molecule annotation
Cholera Enterotoxin, a Chain(Gene symbol: VC1457)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB