| Abstract: | The proteins of the outer membrane of Neisseria gonorrhoeae play an important role in the serotyping system defined by K. H. Johnston et al. (J. Exp. Med. 143:741–758, 1976). This study attempted to delineate the molecular arrangement of the major proteins of the outer membrane of the gonococcus by using three approaches. First, natural protein-protein relationships were demonstrated by symmetrical, two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Second, proteins exposed on the surface of outer membrane vesicles were cross-linked by using the bifunctional reagents dimethyl-3,3′-dithiobispropionimidate and dithiobis[succinimidyl propionate]. Third, specific antigen-antibody interactions on the surface of membrane vesicles were analyzed by radioautographic techniques. The major proteins of the outer membrane of the gonococcus were defined, and a nomenclature was devised to take into account the effects of heat and reducing agents on the resolution of these proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results of cross-linking experiments strongly suggest that two of the major proteins of the gonococcal outer membrane (proteins 1 and 3) form a hydrophobically associated trimeric unit in situ which can be stabilized by selective cross-linking reagents. Results substantiated that these proteins are responsible for imparting serotypic specificity. |
