PDBsum entry 1s5d

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protein ligands metals Protein-protein interface(s) links
Transferase,toxin PDB id
Jmol PyMol
Protein chains
218 a.a. *
103 a.a. *
GOL ×5
GAL ×5
Waters ×603
* Residue conservation analysis
PDB id:
Name: Transferase,toxin
Title: Cholera holotoxin with an a-subunit y30s mutation, crystal f
Structure: Cholera enterotoxin, a chain. Chain: a. Synonym: NAD(+)--diphthamide adp- ribosyltransferase, chole enterotoxin a subunit. Engineered: yes. Mutation: yes. Cholera toxin b protein (ctb). Chain: d, e, f, g, h. Engineered: yes
Source: Vibrio cholerae. Organism_taxid: 666. Gene: ctxa, toxa, vc1457. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008. Gene: ctxb, toxb, vc1456.
Biol. unit: Hexamer (from PQS)
1.75Å     R-factor:   0.163     R-free:   0.191
Authors: C.J.O'Neal,E.I.Amaya,M.G.Jobling,R.K.Holmes,W.G.Hol
Key ref:
C.J.O'Neal et al. (2004). Crystal structures of an intrinsically active cholera toxin mutant yield insight into the toxin activation mechanism. Biochemistry, 43, 3772-3782. PubMed id: 15049684 DOI: 10.1021/bi0360152
20-Jan-04     Release date:   06-Apr-04    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
P01555  (CHTA_VIBCH) -  Cholera enterotoxin subunit A
258 a.a.
218 a.a.
Protein chains
Pfam   ArchSchema ?
P01556  (CHTB_VIBCH) -  Cholera enterotoxin subunit B
124 a.a.
103 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 2 residue positions (black crosses)

 Enzyme reactions 
   Enzyme class: Chain A: E.C.  - NAD(+)--diphthamide ADP-ribosyltransferase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: NAD+ + diphthamide-[translation elongation factor 2] = nicotinamide + N-(ADP-D-ribosyl)diphthamide-[translation elongation factor 2]
+ diphthamide-[translation elongation factor 2]
Bound ligand (Het Group name = GAL)
matches with 40.00% similarity
+ N-(ADP-D-ribosyl)diphthamide-[translation elongation factor 2]
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     extracellular region   6 terms 
  Biological process     killing of cells of other organism   6 terms 
  Biochemical function     catalytic activity     7 terms  


    Added reference    
DOI no: 10.1021/bi0360152 Biochemistry 43:3772-3782 (2004)
PubMed id: 15049684  
Crystal structures of an intrinsically active cholera toxin mutant yield insight into the toxin activation mechanism.
C.J.O'Neal, E.I.Amaya, M.G.Jobling, R.K.Holmes, W.G.Hol.
Cholera toxin (CT) is a heterohexameric bacterial protein toxin belonging to a larger family of A/B ADP-ribosylating toxins. Each of these toxins undergoes limited proteolysis and/or disulfide bond reduction to form the enzymatically active toxic fragment. Nicking and reduction render both CT and the closely related heat-labile enterotoxin from Escherichia coli (LT) unstable in solution, thus far preventing a full structural understanding of the conformational changes resulting from toxin activation. We present the first structural glimpse of an active CT in structures from three crystal forms of a single-site A-subunit CT variant, Y30S, which requires no activational modifications for full activity. We also redetermined the structure of the wild-type, proenzyme CT from two crystal forms, both of which exhibit (i) better geometry and (ii) a different A2 "tail" conformation than the previously determined structure [Zhang et al. (1995) J. Mol. Biol. 251, 563-573]. Differences between wild-type CT and active CTY30S are observed in A-subunit loop regions that had been previously implicated in activation by analysis of the structure of an LT A-subunit R7K variant [van den Akker et al. (1995) Biochemistry 34, 10996-11004]. The 25-36 activation loop is disordered in CTY30S, while the 47-56 active site loop displays varying degrees of order in the three CTY30S structures, suggesting that disorder in the activation loop predisposes the active site loop to a greater degree of flexibility than that found in unactivated wild-type CT. On the basis of these six new views of the CT holotoxin, we propose a model for how the activational modifications experienced by wild-type CT are communicated to the active site.

Literature references that cite this PDB file's key reference

  PubMed id Reference
22466878 K.V.Korotkov, M.Sandkvist, and W.G.Hol (2012).
The type II secretion system: biogenesis, molecular architecture and mechanism.
  Nat Rev Microbiol, 10, 336-351.  
21481325 D.G.Eliasson, A.Helgeby, K.Schön, C.Nygren, K.El-Bakkouri, W.Fiers, X.Saelens, K.B.Lövgren, I.Nyström, and N.Y.Lycke (2011).
A novel non-toxic combined CTA1-DD and ISCOMS adjuvant vector for effective mucosal immunization against influenza virus.
  Vaccine, 29, 3951-3961.  
20844480 N.Lycke, and M.Bemark (2010).
Mucosal adjuvants and long-term memory development with special focus on CTA1-DD and other ADP-ribosylating toxins.
  Mucosal Immunol, 3, 556-566.  
20852644 S.L.Reichow, K.V.Korotkov, W.G.Hol, and T.Gonen (2010).
Structure of the cholera toxin secretion channel in its closed state.
  Nat Struct Mol Biol, 17, 1226-1232.  
19324092 J.Abendroth, D.D.Mitchell, K.V.Korotkov, T.L.Johnson, A.Kreger, M.Sandkvist, and W.G.Hol (2009).
The three-dimensional structure of the cytoplasmic domains of EpsF from the type 2 secretion system of Vibrio cholerae.
  J Struct Biol, 166, 303-315.
PDB codes: 2vma 2vmb 3c1q
18515100 G.Zhang (2008).
Design, synthesis, and evaluation of bisubstrate analog inhibitors of cholera toxin.
  Bioorg Med Chem Lett, 18, 3724-3727.  
18272180 R.S.Ampapathi, A.L.Creath, D.I.Lou, J.W.Craft, S.R.Blanke, and G.B.Legge (2008).
Order-disorder-order transitions mediate the activation of cholera toxin.
  J Mol Biol, 377, 748-760.  
17526733 J.Kato, J.Zhu, C.Liu, and J.Moss (2007).
Enhanced sensitivity to cholera toxin in ADP-ribosylarginine hydrolase-deficient mice.
  Mol Cell Biol, 27, 5534-5543.  
16099990 C.J.O'Neal, M.G.Jobling, R.K.Holmes, and W.G.Hol (2005).
Structural basis for the activation of cholera toxin by human ARF6-GTP.
  Science, 309, 1093-1096.
PDB codes: 2a5d 2a5f 2a5g
The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB codes are shown on the right.