The class 1 outer membrane protein of Neisseria meningitidis: gene sequence and structural and immunological similarities to gonococcal porins

The class 1 protein is a major protein of the outer membrane of Neisseria meningitidis, and an important immunodeterminant in humans. The complete nucleotide sequence for the structural gene of a class 1 protein has been determined. The sequence predicts a protein of 374 amino acids, preceded by a typical signal peptide of 19 residues. The hydropathy profile of the predicted protein sequence resembles that of the Escherichia coli and gonococcal porins. The predicted protein sequence of the class 1 protein exhibits considerable structural similarity to the gonococcal porins PIA and PIB. Western blot studies also reveal immunologically conserved domains between the class 1 protein, PIA and PIB. A restriction fragment from the class 1 gene hybridizes to gonococcal genomic fragments in Southern blots. In addition to the class 1 gene coding region there is a large open reading frame on the opposite strand.