1ha5: Difference between revisions

Revision as of 13:59, 21 February 2008

STRUCTURAL FEATURES OF A ZINC-BINDING SITE IN THE SUPERANTIGEN STREPTOCOCCAL PYROGENIC EXOTOXIN A (SPEA1): IMPLICATIONS FOR MHC CLASS II RECOGNITION.

OverviewOverview

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 StructureAbout this Structure

1HA5 is a Single protein structure of sequence from Streptococcus pyogenes with as ligand. Known structural/functional Site: . Full crystallographic information is available from OCA.

ReferenceReference

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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OCA

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 ==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.
+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==
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 [[Category: Single protein]]
 [[Category: Streptococcus pyogenes]]
-[[Category: Acharya, K.R.]]
+[[Category: Acharya, K R.]]
-[[Category: Baker, M.D.]]
+[[Category: Baker, M D.]]
-[[Category: Collins, C.M.]]
+[[Category: Collins, C M.]]
-[[Category: Gutman, D.M.]]
+[[Category: Gutman, D M.]]
-[[Category: Papageorgiou, A.C.]]
+[[Category: Papageorgiou, A C.]]
 [[Category: ZN]]
 [[Category: exotoxin]]
@@ Line 25: / Line 25: @@
 [[Category: zinc binding]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 09:48:12 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:59:04 2008''