1uns: Difference between revisions
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==Overview== | ==Overview== | ||
The previously determined crystal structure of the superantigen, staphylococcal enterotoxin C2 (SEC2) showed binding of a single zinc ion, located between the N- and C-terminal domains. Here we present the crystal, structure of SEC2 determined to 2.0 A resolution in the presence of, additional zinc. The structure revealed the presence of a secondary, zinc-binding site close to the major histocompatibility complex, (MHC)-binding site of the toxin and some 28 A away from the primary, zinc-binding site of the toxin found in previous studies. T cell, stimulation assays showed that varying the concentration of zinc ions, present affected the activity of the toxin and we observed that high zinc, concentrations considerably inhibited T cell responses. This indicates, that SEC2 may have multiple ... | The previously determined crystal structure of the superantigen, staphylococcal enterotoxin C2 (SEC2) showed binding of a single zinc ion, located between the N- and C-terminal domains. Here we present the crystal, structure of SEC2 determined to 2.0 A resolution in the presence of, additional zinc. The structure revealed the presence of a secondary, zinc-binding site close to the major histocompatibility complex, (MHC)-binding site of the toxin and some 28 A away from the primary, zinc-binding site of the toxin found in previous studies. T cell, stimulation assays showed that varying the concentration of zinc ions, present affected the activity of the toxin and we observed that high zinc, concentrations considerably inhibited T cell responses. This indicates, that SEC2 may have multiple modes of interaction with the immune system, that are dependent on serum zinc levels. The potential role of the, secondary zinc-binding site and that of the primary one in the formation, of the TCR.SEC2.MHC complex are considered, and the possibility that zinc, may regulate the activity of SEC2 as a toxin facilitating different T cell, responses is discussed. | ||
==About this Structure== | ==About this Structure== | ||
1UNS is a | 1UNS 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]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1UNS OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: zinc-binding site]] | [[Category: zinc-binding site]] | ||
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