Preliminary crystallographic investigation of the protein toxin from corynebacterium diphtheriae.

Crystals of diphtheria toxin have been obtained in vapor diffusion experiments from concentrated solutions of potassium tartrate as the precipitating agent. The crystals are trigonal with unit cell dimensions a = b = 97.90 A and c = 100.30 A. The space group is P31 12 or its enantiomorph. The unit cell contains 6 molecules of molecular weight 62,000 with 1 molecule/asymmetric unit. The crystals diffract beyond 2.8 A resolution and are able to withstand more than 100 h of x-ray exposure. The complete structure analysis is in progress.