This region represents the C-terminal 120 amino acids of a family of surface-exposed bacterial proteins. YadA, an adhesin from Yersinia, was the first member of this family to be characterized. UspA2 from Moraxella was second. The Eib immunoglobulin-binding proteins from E. coli were third, followed by the DsrA proteins of Haemophilus ducreyi and others. These proteins are homologous at their C-terminal and have predicted signal sequences, but they diverge elsewhere. The C-terminal 9 amino acids, consisting of alternating hydrophobic amino acids ending in F or W, comprise a targeting motif for the outer membrane of the Gram negative cell envelope. This region is important for oligomerization.