1CK1

STRUCTURE OF STAPHYLOCOCCAL ENTEROTOXIN C3

Summary for 1CK1

• Entry DOI: 10.2210/pdb1ck1/pdb
• Descriptor: PROTEIN (ENTEROTOXIN TYPE C-3), ZINC ION (3 entities in total)
• Functional Keywords: staphylococcal enterotoxin, superantigen, zinc, toxin
• Biological source: Staphylococcus aureus
• Total number of polymer chains: 1
• Total formula weight: 27729.43

Authors

Chi, Y.-I.,Bohach, G.A.,Stauffacher, C.V. (deposition date: 1999-04-26, release date: 2002-07-10, Last modification date: 2024-10-30)

Primary citation

Chi, Y.I.,Sadler, I.,Jablonski, L.M.,Callantine, S.D.,Deobald, C.F.,Stauffacher, C.V.,Bohach, G.A.
Zinc-mediated dimerization and its effect on activity and conformation of staphylococcal enterotoxin type C.
J.Biol.Chem., 277:22839-22846, 2002

PubMed Abstract: Staphylococcal enterotoxins are superantigen exotoxins that mediate food poisoning and toxic shock syndrome in humans. Despite their structural and functional similarities, superantigens display subtle differences in biological properties and modes of receptor binding as a result of zinc atoms bound differently in their crystal structures. For example, the crystal structures of the staphylococcal enterotoxins in the type C serogroup (SECs) contain a zinc atom coordinated by one aspartate and two histidine residues from one molecule and another aspartate residue from the next molecule, thus forming a dimer. This type of zinc ligation and zinc-mediated dimerization occurs in several SECs, but not in most other staphylococcal enterotoxin serogroups. This prompted us to investigate the potential importance of zinc in SEC-mediated pathogenesis. Site-directed mutagenesis was used to replace SEC zinc binding ligands with alanine. SEC mutants unable to bind zinc did not have major conformational alterations although they failed to form dimers. Zinc binding was not essential for T cell stimulation, emesis, or lethality although in general the mutants were less pyrogenic. Thus the zinc atom in SECs might represent a non-functional heavy atom in an exotoxin group that has diverged from related bacterial toxins containing crucial zinc atoms.

PubMed: 11934896
DOI: 10.1074/jbc.M201932200

Experimental method

X-RAY DIFFRACTION (2.6 Å)