1dt2
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(New page: 200px<br /><applet load="1dt2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1dt2, resolution 2.8Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 11:26, 20 November 2007
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CRYSTAL STRUCTURE OF EXFOLIATIVE TOXIN B
Overview
Staphylococcal aureus epidermolytic toxins (ETs) A and B are responsible, for the induction of staphylococcal scalded skin syndrome, a disease of, neonates and young children. The clinical features of this syndrome vary, from localized blisters to severe exfoliation affecting most of the body, surface. Comparison of the crystal structures of two subtypes of ETs-rETA, (at 2.0 A resolution), rETB (at 2.8 A resolution), and an active site, variant of rETA, Ser195Ala at 2.0 A resolution has demonstrated that their, overall topology resembles that of a "trypsin-like" serine protease, but, with significant differences at the N- and C-termini and loop regions. The, details of the catalytic site in both ET structures are very similar to, those in glutamate-specific serine proteases, suggesting a common, catalytic mechanism. However, the "oxyanion hole," which is part of the, catalytic sites of glutamate specific serine proteases, is in the closed, or inactive conformation for rETA, yet in the open or active conformation, for rETB. The ETs contain a unique amphipathic helix at the N-terminus, and it appears to be involved in optimizing the conformation of the, catalytic site residues. Determination of the structure of the rETA, catalytic site variant, Ser195Ala, showed no significant perturbation at, the active site, establishing that the loss of biological and esterolytic, activity can be attributed solely to disruption of the catalytic serine, residue. Finally, the crystal structure of ETs, together with biochemical, data and mutagenesis studies, strongly confirms the classification of, these molecules as "serine proteases" rather than "superantigens."
About this Structure
1DT2 is a Single protein structure of sequence from Staphylococcus aureus. Full crystallographic information is available from OCA.
Reference
Structural similarities and differences in Staphylococcus aureus exfoliative toxins A and B as revealed by their crystal structures., Papageorgiou AC, Plano LR, Collins CM, Acharya KR, Protein Sci. 2000 Mar;9(3):610-8. PMID:10752623
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