ISOLATION OF THE PERIPLASM OF NEISSERIA-GONORRHOEAE

The periplasm of Neisseria gonorrhoeae should be similar to other Gram -negative bacteria, but no published reports confirm this assumption. We used a periplasmic isolation procedure developed in Escherichia col i to release the periplasmic contents of N. gonorrhoeae. The resultant periplasmic extract lacked lipopolysaccharide, protein markers of inn er or outer membranes, surface-radiolabelled protein components, or ri bosomal proteins. The periplasmic extract contained a single haem prot ein believed to be a c-type cytochrome known to exist in the periplasm of other Gram-negative species, and retained significant alkaline pho sphatase activity. The dominant protein species released in the peripl asmic extract was the gonococcal homologue of elongation factor Tu, a major component released in similar periplasmic extracts of E. coli. T hese data showed that the extraction procedure selectively released pe riplasmic components and that the gonococcal periplasm was comparable to that of E. coli. Further analysis of the gonococcal periplasm may p rovide important insights into the physiology of this pathogen of huma ns.