Binds (in a non-immune fashion) to the Fc portion of human IgG and very weakly to IgA; binding occurs on the cell surface. Confers the ability to survive exposure to human serum exposure. Homotrimer; can probably form mixed heterotrimers in vivo (By similarity). In denaturing gels runs as a band of about 180 kDa (PubMed:10722621). The C-terminal translocator domain is localized in the outer membrane and the passenger domain is at the cell surface. In strain ECOR 9 expression is greater at 37 than 27 degrees Celsius and increases upon entry into stationary phase (at protein level). Upon expression from a plasmid in strain AB1157 (with its own leader sequence) more protein is seen at 37 than 27 degrees Celsius (at protein level). Encoded in a prophage region of strain ECOR 9, upon UV treatment bacteriophage containing this gene can be isolated. Belongs to the autotransporter-2 (AT-2) (TC 1.B.40) family. Eib subfamily.