This family consists of several repeats of 31 residues in length and seems to be exclusive to Moraxella catarrhalis UspA proteins. The UspA1 and UspA2 proteins of Moraxella catarrhalis are structurally related and are exposed on the bacterial cell surface where can function adhesins [1]. This family is commonly found with the Pfam:PF03895 family.

1: The UspA1 protein and a second type of UspA2 protein mediate adherence of Moraxella catarrhalis to human epithelial cells in vitro. Lafontaine ER, Cope LD, Aebi C, Latimer JL, McCracken GH Jr, Hansen EJ; J Bacteriol 2000;182:1364-1373. PMID:10671460