REFINED STRUCTURES OF 3 CRYSTAL FORMS OF TOXIC SHOCK SYNDROME TOXIN-1AND OF A TETRAMUTANT WITH REDUCED ACTIVITY

The structure of toxic shock syndrome toxin-1 (TSST-1), the causative agent in toxic shock syndrome, has been determined in three crystal fo rms. The three structural models h;ave been refined to R-factors of 0. 15 4, 0.150, and 0.198 at resolutions of 2.05 Angstrom, 2.90 Angstrom, and 2.75 Angstrom, respectively. One crystal form of TSST-1 contains a zinc ion bound between two symmetry-related molecules. Although not required for biological activity, zinc dramatically potentiates the mi togenicity of TSST-1 at very low concentrations. In addition, the stru cture of the tetramutant TSST-1H [T69I, Y80W, E132K, I140T], which is nonmitogenic and does not amplify endotoxin shock, has been determined and refined in a fourth crystal form (R-factor = 0.173 to 1.9 Angstro m resolution).