Fig. 1

Neisseria gonorrhoeae penicillin-binding protein 2 (PBP 2) amino acid sequences in strains with resistance or decreased susceptible to cefixime. a The dendrogram analysis of amino acid sequences included 12 PBP 2 sequences from N. gonorrhoeae with resistance and decreased susceptibility to cefixime and a wild-type (WT) PBP 2 sequence (M32091). Lower half contains the wild-type PBP 2 sequence and amino acid alterations in the non-mosaic PBP2 XI, XIII and VII, which possessed two amino acid substitutions compared to WT. Upper half displays the mosaic PBP 2 X, XXXI and XXXIV and their single amino acid variants that were found in this study. The numbers of isolates in this study are shown in parentheses. b Amino acid sequence similarities of mosaic PBP 2 (X, XXXIV and XXVI) and WT are shown. The boundary of N- and C-terminal domain is from the crystal structure of PBP 2 derived from the penicillin-resistant strain FA19 [33]. The N-terminal domain (1–239) of the mosaic PBP 2 sequences are similar to WT (over 96.7 %), but the C-terminal domains of mosaic PBP 2 show lower similarity: 86.4 % for PBP 2 X and PBP 2 XXXIV and 87.7 % for XXVI compared to WT. PBP 2 X is identical to PBP 2 XXXIV, except for the C-terminal end (549–582, where seven amino acids differ). The C-terminal end of PBP 2 XXXIV is identical with that of WT, whereas that of PBP 2 X is identical to PBP 2 XXVI, although the C-terminal domain of PBP 2 XXVI differs from the mosaic PBP 2 X and XXXIV (97.7 % identity). For detailed amino acid sequences of these and other PBP 2’s, see Ohnishi et al. [7]