Identification and characterization of a Neisseria gonorrhoeae gene encoding a glycolipid-binding adhesin

We recently identified a set of mammalian cell receptors for Neisseria gonorrhoeae that are glycolipids. These receptors, lactosylceramide [Gal(β1-4)Glc(β1-l)Cer], gangliotriosylceramide [GalNAc(β1-4)Gal(β1-4)Glc(β1-1)Cer], and gangliotetraosylceramide [Gal(β1-3)GalNAc(β1-4)Gal(β1-4)Glc(β1-1)Cer], were shown to be specifically bound by a gonococcal outer membrane protein distinct from pilin and protein II. Here we report the isolation of the gene encoding the gangliotetraosylceramide-binding adhesin from a N. gonorrhoeae MS11 gene bank in Escherichia coli. Transposon mutagenesis studies in E. coli indicate that the adhesin is a protein with a molecular mass of 36,000 Da. The gene encoding the 36-kDa protein is duplicated in MS11 since two transposon insertions were required to abolish expression of the gene in this bacterium. This protein is present on the surface of the gonococcus and is not associated with the pilus.