FIG. 1.

Sequence variants and polymorphic nucleotide sites in each of the highly polymorphic segments of the porB1a alleles, encoding amino acid loops of the mature PorB1a protein (29), of N. gonorrhoeae isolates (n = 22). The nucleotide present at each polymorphic site among all of the sequence variants is shown for sequence variant 1 in each loop segment. For the other sequence variants, those sites that differ are shown. Dots indicate identity with sequence variant 1, and underlining indicates synonymous mutations. Nucleotide sites that are conserved in all sequence variants are excluded. The length of each loop segment is included, and the sites are numbered above in vertical format based on the nucleotide numbering of a porB1a gene (GenBank accession no. J03029).