2a5f | pdb_00002a5f
Cholera toxin A1 subunit bound to its substrate, NAD+, and its human protein activator, ARF6
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Overview
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.
About this Structure
2A5F is a Protein complex structure of sequences from Homo sapiens and Vibrio cholerae with MG, NA, GTP, NAD and GOL as ligands. Active as NAD(+)--diphthamide ADP-ribosyltransferase, with EC number 2.4.2.36 Full crystallographic information is available from OCA.
Reference
Structural basis for the activation of cholera toxin by human ARF6-GTP., O'Neal CJ, Jobling MG, Holmes RK, Hol WG, Science. 2005 Aug 12;309(5737):1093-6. PMID:16099990
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