1b1z
From Proteopedia
(New page: 200px<br /><applet load="1b1z" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b1z, resolution 2.57Å" /> '''STREPTOCOCCAL PYROGE...) |
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| - | [[Image:1b1z.gif|left|200px]]<br /><applet load="1b1z" size=" | + | [[Image:1b1z.gif|left|200px]]<br /><applet load="1b1z" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1b1z, resolution 2.57Å" /> | caption="1b1z, resolution 2.57Å" /> | ||
'''STREPTOCOCCAL PYROGENIC EXOTOXIN A1'''<br /> | '''STREPTOCOCCAL PYROGENIC EXOTOXIN A1'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Streptococcal pyrogenic exotoxin A (SpeA) is a superantigen produced by | + | Streptococcal pyrogenic exotoxin A (SpeA) is a superantigen produced by Streptococcus pyogenes and is associated with severe infections characterized by rash, hypotension, multiorgan failure and a high mortality rate. In this study, an allelic form of this toxin, SpeA1, was crystallized with four molecules in the crystallographic asymmetric unit and its crystal structure was determined at 2.6 A resolution. The crystallographic R-factor was 19.4% (33 497 reflections) for 7031 protein atoms and 88 water molecules. The overall structure of SpeA1 is considerably similar to that of other prototype microbial superantigens, either of staphylococcal or streptococcal origin, but has greatest similarity to staphylococcal enterotoxin C (SEC). Based on structural and mutagenesis data, we have mapped several important residues on the toxin molecule, which are involved in the recognition of major histocompatibility complex (MHC) class II molecules and T-cell receptors. Also, the toxin appears to possess a potential zinc-binding site which may have implications in binding to particular MHC class II molecules. Finally, we propose models for SpeA1-MHC class II and SpeA1-T-cell receptor association and the relevance of this phenomenon to the superantigenic action of this toxin is considered. |
==About this Structure== | ==About this Structure== | ||
| - | 1B1Z is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_pyogenes Streptococcus pyogenes]. Full crystallographic information is available from [http:// | + | 1B1Z is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_pyogenes Streptococcus pyogenes]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B1Z OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptococcus pyogenes]] | [[Category: Streptococcus pyogenes]] | ||
| - | [[Category: Acharya, K | + | [[Category: Acharya, K R.]] |
| - | [[Category: Papageorgiou, A | + | [[Category: Papageorgiou, A C.]] |
[[Category: pyrogenic exotoxin]] | [[Category: pyrogenic exotoxin]] | ||
[[Category: superantigen]] | [[Category: superantigen]] | ||
[[Category: zinc binding]] | [[Category: zinc binding]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:50:34 2008'' |
Revision as of 09:50, 21 February 2008
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STREPTOCOCCAL PYROGENIC EXOTOXIN A1
Overview
Streptococcal pyrogenic exotoxin A (SpeA) is a superantigen produced by Streptococcus pyogenes and is associated with severe infections characterized by rash, hypotension, multiorgan failure and a high mortality rate. In this study, an allelic form of this toxin, SpeA1, was crystallized with four molecules in the crystallographic asymmetric unit and its crystal structure was determined at 2.6 A resolution. The crystallographic R-factor was 19.4% (33 497 reflections) for 7031 protein atoms and 88 water molecules. The overall structure of SpeA1 is considerably similar to that of other prototype microbial superantigens, either of staphylococcal or streptococcal origin, but has greatest similarity to staphylococcal enterotoxin C (SEC). Based on structural and mutagenesis data, we have mapped several important residues on the toxin molecule, which are involved in the recognition of major histocompatibility complex (MHC) class II molecules and T-cell receptors. Also, the toxin appears to possess a potential zinc-binding site which may have implications in binding to particular MHC class II molecules. Finally, we propose models for SpeA1-MHC class II and SpeA1-T-cell receptor association and the relevance of this phenomenon to the superantigenic action of this toxin is considered.
About this Structure
1B1Z is a Single protein structure of sequence from Streptococcus pyogenes. Full crystallographic information is available from OCA.
Reference
Structural basis for the recognition of superantigen streptococcal pyrogenic exotoxin A (SpeA1) by MHC class II molecules and T-cell receptors., Papageorgiou AC, Collins CM, Gutman DM, Kline JB, O'Brien SM, Tranter HS, Acharya KR, EMBO J. 1999 Jan 4;18(1):9-21. PMID:9878045
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