1ck1
From Proteopedia
(New page: 200px<br /><applet load="1ck1" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ck1, resolution 2.60Å" /> '''STRUCTURE OF STAPHYL...) |
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| - | [[Image:1ck1.jpg|left|200px]]<br /><applet load="1ck1" size=" | + | [[Image:1ck1.jpg|left|200px]]<br /><applet load="1ck1" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ck1, resolution 2.60Å" /> | caption="1ck1, resolution 2.60Å" /> | ||
'''STRUCTURE OF STAPHYLOCOCCAL ENTEROTOXIN C3'''<br /> | '''STRUCTURE OF STAPHYLOCOCCAL ENTEROTOXIN C3'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Staphylococcal enterotoxins are superantigen exotoxins that mediate food | + | 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. |
==About this Structure== | ==About this Structure== | ||
| - | 1CK1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus] with ZN as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1CK1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus] with <scene name='pdbligand=ZN:'>ZN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CK1 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Staphylococcus aureus]] | [[Category: Staphylococcus aureus]] | ||
| - | [[Category: Bohach, G | + | [[Category: Bohach, G A.]] |
| - | [[Category: Chi, Y | + | [[Category: Chi, Y I.]] |
| - | [[Category: Stauffacher, C | + | [[Category: Stauffacher, C V.]] |
[[Category: ZN]] | [[Category: ZN]] | ||
[[Category: staphylococcal enterotoxin]] | [[Category: staphylococcal enterotoxin]] | ||
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[[Category: zinc]] | [[Category: zinc]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:06:55 2008'' |
Revision as of 10:06, 21 February 2008
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STRUCTURE OF STAPHYLOCOCCAL ENTEROTOXIN C3
Overview
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.
About this Structure
1CK1 is a Single protein structure of sequence from Staphylococcus aureus with as ligand. Full crystallographic information is available from OCA.
Reference
Zinc-mediated dimerization and its effect on activity and conformation of staphylococcal enterotoxin type C., Chi YI, Sadler I, Jablonski LM, Callantine SD, Deobald CF, Stauffacher CV, Bohach GA, J Biol Chem. 2002 Jun 21;277(25):22839-46. Epub 2002 Apr 4. PMID:11934896
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