<p> Members of this protein family are restricted to the Proteobacteria. Each contains a C-terminal sortase-recognition motif, transmembrane domain, and basic residues cluster at the the C terminus, and is encoded adjacent to a sortase gene. This protein is frequently the only sortase target in its genome, which is as unusual its occurrence in Gram-negative rather than Gram-positive genomes. Many bacteria with this system are marine. In addition to the LPXTG signal, members carry a vault protein inter-alpha-trypsin inhibitor domain (<db_xref db="PFAM" dbkey="PF08487"/>) and a von Willebrand factor type A domain (<db_xref db="PFAM" dbkey="PF00092"/>). </p> Conserved hypothetical protein CHP03788