High-resolution X-ray crystallographic techniques have led to the elucidation of the 3-D structure of five S. pyogenes SAgs, namely, SPE C, SPE A, SSA, SPE H, and SMEZ-2. All of these toxins as well as S. aureus SAgs investigated to date appear as compacted ellipsoidal proteins sharing a common characteristic two-domain folding pattern comprising a NH2-terminal p barrel globular domain, a long a helix that diagonally spans the center of the molecule, and a COOH-terminal globular domain based on grasp motif. Valuable information on the molecular architecture of MHC-SAg-TcR complexes was obtained by X-ray crystallography of the SAgs bound to human MHC class II molecules and (or) TcR.[14,18,19]
These studies revealed the essential role of Zn in this process for certain SAgs.
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The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.