Protein Domain : Adhesin operon regulatory protein IPR004356

Type	Family
Description	Proteins in this family include PapB, DaaA, FanA, FanB and AfaA.P pili, or fimbriae, are ~68A in diameter and 1 micron in length, the bulk of which is a fibre composed of the main structural protein PapA [].At its tip, the pilus is terminated by a fibrillum consisting of repeating units of the PapE protein. This, in turn, is topped by the adhesins, PapFand PapG, both of which are needed for receptor binding. The tip fibrillum is anchored to the main PapA fibre by the PapK pilus-adaptor protein. PapH,an outer membrane protein, then anchors the entire rod in the bacterial envelope []. A cytoplasmic chaperone (PapD) assists in assembling the monomers of the macromolecule in the membrane. All of the functional pap genes are arranged in a cluster (operon) on the Escherichia coli genome. It is believed that selective pressure exerted by the host's urinal and intestinal tract isoreceptors forced the spread of this operon to other strains via lateral transfer []. PapB, encoded within the cluster, acts as a transcriptional regulator of the functional pap genes and is located in the bacterial cytoplasm []. Its mechanism involvesdifferential binding to separate sites in the cluster, suggesting that this protein is both an activator and repressor of pilus-adhesion transcription. The protein shares similarity with other E. coli fimbrial- adhesion transcription regulators, such as AfaA, DaaA and FanB.
Short Name	Adhesin_operon_reg_prot