On the pathogenesis of diphtheria

Summary By means of the paper-chromatographic method an attempt was made to gain an insight into the excretion of amino-acids in the saliva of adult men and women. The amino-acids in this saliva were separated from accompanying obstructives (mucines, proteins, etc.) by dialysis through cellophane membranes. The fairly large quantities of salts were removed by electrolysis. We obtained “twodimensional chromatograms”, phenol and a mixture of collidine and lutidine having been used as solvents. With respect to the above-mentioned excretion of amino-acids in the saliva of 50 adult men and 50 ditto women, there were notable differences between the sexes. On the whole, the examined saliva samples of the women presented a fairly uniform picture. Only one amino-acid pattern showed more than 10 amino-acids. Among the 50 men, on the other hand, there were 10 cases where the examined saliva samples contained from 11 to 15 amino-acids. Quantitatively, too, a distinct difference between the sexes could be demonstrated. With the exception of valine and taurine, the men excrete larger quantities of all the amino-acids in their saliva, than the women whose saliva was examined. Part I:A. Tasman andL. Smith, Antonie van Leeuwenhoek19, 135, 1953.     

Crystallization of diphtheria toxin.

Two new crystal forms (forms III and IV) have been grown of diphtheria toxin (DT), which kills susceptible cells by catalyzing the ADP-ribosylation of elongation factor 2, thereby stopping protein synthesis. Forms III and IV diffract to 2.3 A and 2.7 A resolution, respectively. Both forms belong to space group C2; the unit cell parameters for form III are a = 107.3 A, b = 91.7 A, c = 66.3 A and beta = 94.7 degrees and those for form IV are a = 108.3 A, b = 92.3 A, c = 66.1 A and beta = 90.4 degrees. Both forms have one protein chain per asymmetric unit with the dimeric molecule on a twofold axis of symmetry. Form IV is exceptional among all crystal forms of DT in that it can be grown reproducibly. Thus the form IV crystals should yield a crystallographic structure giving insight into the catalytic, receptor-binding and membrane-insertion properties of DT.