CRYSTALLIZATION AND PRELIMINARY-X-RAY STUDIES OF THE DIPHTHERIA TOX REPRESSOR FROM CORYNEBACTERIUM-DIPHTHERIAE

Crystals of the diphtheria tox repressor (DtxR) from Corynebacterium d iphtheriae suitable for structure determination have been obtained. Dt xR activated with transition metal ions represses the expression of th e structural gene for the diphtheria toxin, tox, which is encoded on t he genome of a family of closely related corynebacteriophages. The spa ce group of the obtained crystals is trigonal P3(1)21 or its enantiomo rph P3(2)21 with a = b = 64.2 Angstrom, c = 220.5 Angstrom, alpha = be ta = 90 degrees, gamma = 120 degrees. Two monomers comprise the asymme tric unit. The crystals diffract to a resolution of better than 3 Angs trom.