217 proteins have, contrary to expectations, been found in the membrane of Neisseria meningitidis. Of these 217, 76 in particular evaded all algorithmic methods for predicting membrane localisation. Existing knowledge of protein trafficking pathways in meningococcus does not explain how or why these proteins are located in the bacterial membrane e.g. there is no apparent biochemical reason for a DNA helicase or a chromosomal replication initiator protein to be found in the membrane. These 217 proteins are provided as membrane proteins.