1qil: Difference between revisions
New page: left|200px<br /><applet load="1qil" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qil, resolution 2.5Å" /> '''INACTIVE MUTANT TOXIC... |
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[[Image:1qil.gif|left|200px]]<br /><applet load="1qil" size=" | [[Image:1qil.gif|left|200px]]<br /><applet load="1qil" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1qil, resolution 2.5Å" /> | caption="1qil, resolution 2.5Å" /> | ||
'''INACTIVE MUTANT TOXIC SHOCK SYNDROME TOXIN-1 AT 2.5 A'''<br /> | '''INACTIVE MUTANT TOXIC SHOCK SYNDROME TOXIN-1 AT 2.5 A'''<br /> | ||
==Overview== | ==Overview== | ||
Toxic shock syndrome toxin-1 (TSST-1) is one of a family of staphylococcal | Toxic shock syndrome toxin-1 (TSST-1) is one of a family of staphylococcal exotoxins recognized as microbial superantigens. The toxin plays a dominant role in the genesis of toxic shock in humans through a massive activation of the immune system. This potentially lethal illness occurs as a result of the interaction of TSST-1 with a significant proportion of the T-cell repertoire. TSST-1, like other superantigens, can bind directly to class II major histocompatibility (MHC class II) molecules prior to its interaction with entire families of V beta chains of the T-cell receptor (TCR). The three-dimensional structure of a mutant (His-135-Ala) TSST-1 was compared with the structure of the native (wild-type) TSST-1 at 2.5 A resolution. The replacement of His 135 of TSST-1 with an Ala residue results in the loss of T-cell mitogenicity and toxicity in experimental animals. This residue, postulated to be directly involved in the toxin-TCR interactions, is located on the major helix alpha 2, which forms the backbone of the molecule and is exposed to the solvent. In the molecular structure of the mutant toxin, the helix alpha 2 remains unaltered, but the His to Ala modification causes perturbations on the neighboring helix alpha 1 by disrupting helix-helix interactions. Thus, the effects on TCR binding of the His 135 residue could actually be mediated, wholly or in part, by the alpha 1 helix. | ||
==About this Structure== | ==About this Structure== | ||
1QIL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus]. Full crystallographic information is available from [http:// | 1QIL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QIL OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Staphylococcus aureus]] | [[Category: Staphylococcus aureus]] | ||
[[Category: Acharya, K | [[Category: Acharya, K R.]] | ||
[[Category: Papageorgiou, A | [[Category: Papageorgiou, A C.]] | ||
[[Category: staphylococcal enterotoxin]] | [[Category: staphylococcal enterotoxin]] | ||
[[Category: superantigen]] | [[Category: superantigen]] | ||
[[Category: toxin]] | [[Category: toxin]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:39:59 2008'' | ||
Revision as of 15:40, 21 February 2008
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INACTIVE MUTANT TOXIC SHOCK SYNDROME TOXIN-1 AT 2.5 A
OverviewOverview
Toxic shock syndrome toxin-1 (TSST-1) is one of a family of staphylococcal exotoxins recognized as microbial superantigens. The toxin plays a dominant role in the genesis of toxic shock in humans through a massive activation of the immune system. This potentially lethal illness occurs as a result of the interaction of TSST-1 with a significant proportion of the T-cell repertoire. TSST-1, like other superantigens, can bind directly to class II major histocompatibility (MHC class II) molecules prior to its interaction with entire families of V beta chains of the T-cell receptor (TCR). The three-dimensional structure of a mutant (His-135-Ala) TSST-1 was compared with the structure of the native (wild-type) TSST-1 at 2.5 A resolution. The replacement of His 135 of TSST-1 with an Ala residue results in the loss of T-cell mitogenicity and toxicity in experimental animals. This residue, postulated to be directly involved in the toxin-TCR interactions, is located on the major helix alpha 2, which forms the backbone of the molecule and is exposed to the solvent. In the molecular structure of the mutant toxin, the helix alpha 2 remains unaltered, but the His to Ala modification causes perturbations on the neighboring helix alpha 1 by disrupting helix-helix interactions. Thus, the effects on TCR binding of the His 135 residue could actually be mediated, wholly or in part, by the alpha 1 helix.
About this StructureAbout this Structure
1QIL is a Single protein structure of sequence from Staphylococcus aureus. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of a biologically inactive mutant of toxic shock syndrome toxin-1 at 2.5 A resolution., Papageorgiou AC, Quinn CP, Beer D, Brehm RD, Tranter HS, Bonventre PF, Acharya KR, Protein Sci. 1996 Aug;5(8):1737-41. PMID:8844860
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