1. Alignment of N-terminal sequences of type IV pilin proteins.
Alignment of N-terminal sequences of type IV pilin proteins. The leader peptide and first 40 N-terminal residues of representative mature type IV pilin protein sequences were aligned based on the prepilin peptidase cleavage site (marked by an arrow). Pilin-like proteins share the type III signal sequence, which is cleaved before the hydrophobic stretch between the Gly (−1) and Phe (+1) residues, although the +1 residue can vary. The consensus signal sequence used by the PilFind algorithm (195) to identify putative type IV pilin proteins is shown below the alignment. The hydrophobic N terminus of mature pilin proteins is situated in the inner membrane and contains the highly conserved Glu5 (+5) residue (shown in bold); in GspK orthologs, there is a hydrophobic residue at that position. The transmembrane segments, as predicted by Geneious Pro v5.0.3 (Biomatters Ltd.) using TMHMM, are highlighted in blue. Pa, P. aeruginosa; Vc, V. cholerae; Aa, Aggregatibacter (Actinobacillus) actinomycetemcomitans; Mm, Methanococcus maripaludis; Nm, N. meningitidis; ETEC, enterotoxigenic E. coli; Bs, Bacillis subtilis; Mv, Methanococcus voltae.
Carmen L. Giltner et al. Microbiol. Mol. Biol. Rev. 2012; doi: /MMBR