Neisseria gonorrhoeae (gonococcus [Ng]) is the causative organism of the sexually transmitted disease gonorrhoea, and the organism is listed by the World Health Organization as a high-priority pathogen for research and development of new control measures, including vaccines. In this study, we demonstrated that the N. gonorrhoeae adhesin complex protein (Ng-ACP) was conserved and expressed by 50 gonococcal strains and that recombinant proteins induced antibodies in mice that killed the bacteria in vitro . We determined the structure of Ng-ACP by X-ray crystallography and investigated structural conservation with Neisseria meningitidis ACP and MliC/PliC proteins from other bacteria which act as inhibitors of the human innate defense molecule lysozyme. These findings are important and suggest that Ng-ACP could provide a potential dual target for tackling gonococcal infections.