The A, B, and W domains of PrtR. (A) Alignment of the A-domain segments of L. rhamnosus PrtR with conserved residues from PrtP (L. lactis), PrtH (L. helveticus), PrtB (L. delbrueckii subsp. bulgaricus), Csp (S. agalactiae), and ScpA (S. pyogenes). Consensus residues were derived from an alignment of known CEPs; uppercase indicates identical residues, and lowercase indicates highly conserved residues (50). (B) Comparison of B-domain segments of PrtR with conserved sequences residues of PrtP and consensus residues derived from known CEPs. Consensus residues (Con.) are as described for panel A. Identical amino acids are shaded in black; homologous residues are shaded in grey. (C) Alignment of the W domain of PrtR from L. rhamnosus strain BGT10 and the C-terminal part of SspB from S. gordonii (8). Identical amino acids are shaded in black; homologous residues are shaded in grey.(D) Alignment of the W domain of PrtR from L. rhamnosus strain BGT10 and a fragment of the human intestinal mucin (IMuc) (18). Identical amino acids are shaded in black; homologous residues are shaded in grey.