The surface of Neisseria gonorrhoeae: isolation of the major components of the outer membrane.

Outer membranes were isolated from several strains of Neisseria gonorrhoeae by extraction of whole cells with aqueous lithium acetate. The preparations contained a limited number of components including lipopolysaccharide and two major proteins. One protein was present in all strains examined; the second, which showed anomalous behaviour on sodium dodecyl sulphate-polyacrylamide gel electrophoresis, was absent from some. Fluorescent labelling of intact N. gonorrhoeae showed that the two proteins and pili were the major surface proteins. Each of the three major outer membrane components was isolated in a homogeneous form by selective extraction followed by gel filtration.