Studies on gonococcus infection. XIV. Cell wall protein differences among color/opacity colony variants of Neisseria gonorrhoeae.

Gonococci from colonies exhibiting optical opacity and dark coloration have surface proteins that are not visualized in isogenic transparent, light-colored colony forms. These "colony opacity-associated proteins" have apparent molecular weights varying from 24,000 to 30,000 by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate; their apparent molecular weights are independent of that for their major outer membrane protein. The opacity-associated proteins are more susceptible to hydrolysis by trypsin than is the major outer membrane protein, but gonococci possessing the opacity-associated protein(s) also show enhanced susceptibility of their major outer membrane proteins to the action of trypsin. These conclusions were reached by comparing the electrophoretic patterns of whole-cell lysates from both "laboratory strains" and several recent clinical isolates of Neisseria gonorrhoeae.