1S5B	Transerase,Toxin	date	Jan 20, 2004
title	Cholera Holotoxin With An A-Subunit Y30s Mutation Form 3
authors	C.J.O'Neal, E.I.Amaya, M.G.Jobling, R.K.Holmes, W.G.Hol
compound		source
Molecule: Cholera Enterotoxin, A Chain Precursor Chain: A Synonym: Nad(+)--Diphthamide Adp- Ribosyltransferase, Cholera Enterotoxin A Subunit; Ec: 2.4.2.36 Engineered: Yes Mutation: Yes		Organism_scientific: Vibrio Cholerae Organism_common: Bacteria Gene: Ctxa, Toxa, Vc1457 Expression_system: Escherichia Coli Expression_system_common: Bacteria Expression_system_strain: Bl21(De3) Expression_system_vector_type: Plasmid Expression_system_plasmid: Peia154
Molecule: Cholera Toxin B Protein (Ctb) Chain: D, E, F, G, H Engineered: Yes		Organism_scientific: Vibrio Cholerae Organism_common: Bacteria Gene: Ctxb, Toxb, Vc1456 Expression_system: Escherichia Coli Expression_system_common: Bacteria Expression_system_strain: Bl21(De3) Expression_system_vector_type: Plasmid Expression_system_plasmid: Peia154
symmetry	Space Group: P 1 21 1	R_factor	0.177
crystal cell	length a length b length c angle alpha angle beta angle gamma 60.104 107.431 65.950 90.00 91.29 90.00
method	X-Ray Diffraction	resolution	2.13 Å
ligand	NA	enzyme	NAD+-diphthamide ADP-ribosyltransferase;. ADP-ribosyltransferase;. Mono(ADPribosyl)transferase;. NAD-diphthamide ADP-ribosyltransferase. Transferase E.C.2.4.2.36 BRENDA
domain	The four c-terminal residues of the a2 chain occupy the central pore of the holotoxin. Deletion of this residues weakens the interaction between the a subunit and the b pentamer whithout impairing the pentamer formation.
similarity	Belongs to the Enterotoxin_b family.
subunit	The a subunit contains two chains, a1 and a2, linked by a disulfide bridge. The holotoxin (choleragen) consists of a pentameric ring of b subunits whose central pore is occupied by the a subunit.
catalytic activ.	Nad(+) + peptide diphthamide = nicotinamide + peptide n-(adp-d-ribosyl)diphthamide.
genes	HEGFL, HBEGF (H. sapiens); ctxA, ctxB (V. cholerae); EFT2 (S. cerevisiae)
function	This leads to an overproduction of camp and eventually to a hypersecretion of chloride and bicarbonate followed by water, resulting in the characteristic cholera stool. The a2 chain tethers a1 to the pentameric ring. The a1 chain catalyzes the adp-ribosylation of gs alpha, a gtp-binding regulatory protein, to activate the adenylate cyclase. It can bind five gm1 gangliosides. The b subunit pentameric ring directs the a subunit to its target by binding to the gm1 gangliosides present on the surface of the intestinal epithelial cells. It has no toxic activity by itself.
Gene Ontology	Chain Function Process Component A catalytic activity transferase activity transferase activity, transf... NAD+-diphthamide ADP-ribosyl... pathogenesis extracellular region H, F, D, G, E pathogenesis extracellular region membrane
disease	Diphtheria,susceptibility to
Primary reference	Crystal Structures of an Intrinsically Active Cholera Toxin Mutant Yield Insight into the Toxin Activation Mechanism(,)., O'Neal CJ, Amaya EI, Jobling MG, Holmes RK, Hol WG, Biochemistry 2004 Apr 6;43(13):3772-3782. PMID:15049684

Data retrieval

Asymmetric unit, PDB entry: [header only] [complete with coordinates] (145 Kb) [Save to disk] Biological Unit Coordinates (1s5b.pdb1.gz) 122 Kb CSU: Contacts of Structural Units for 1S5B Likely Quarternary Molecular Structure file(s) for 1S5B Structure Factors (645 Kb) Retrieve 1S5B in mmCIF format [Save to disk]

View 1S5B in 3D

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Visual 3D analysis of 1S5B

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Structure-derived information

Electron Density related parameters from EDS Electron Density Server, at Upsala Dipole moment, from Dipole Server at Weizmann Institute Crystal Contacts, from CryCo at Weizmann Institute 3D motif for 1S5B, from MSDmotif at EBI Classification of representative domains in scop (Structural Classification of Proteins)     - Domain d1s5ba_, region A [Jmol] [rasmolscript] [script source]     - Domain d1s5bd_, region D [Jmol] [rasmolscript] [script source]     - Domain d1s5be_, region E [Jmol] [rasmolscript] [script source]     - Domain d1s5bf_, region F [Jmol] [rasmolscript] [script source]     - Domain d1s5bg_, region G [Jmol] [rasmolscript] [script source]     - Domain d1s5bh_, region H [Jmol] [rasmolscript] [script source] Fold representative 1s5b from FSSP and Dali (Families of Structurally Similar Proteins) Class (fold), Architecture (subfold), Topology, Homologous superfamily from CATH Summaries and structural analyses of PDB data files from PDBSum Identification of Protein Pockets & Cavities at CASTp

Sequence-derived information

View one-letter amino acid or nucleotide sequence for each chain: [1s5b_A] [1s5b_G] [1s5b_D] [1s5b_E] [1s5b_F] [1s5b_H]

Other resources with information on 1S5B

InterPro: IPR001144 , IPR001835 MMDB (Entrez's Structure Database)

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