Fimbrillin-A associated anchor proteins Mfa1 and Mfa2
This family of proteins may be lipoproteins principally from bacilli. They are between 300 and 400 residues. Many Bacteroides-like bacterial species, including Porphyromonas gingivalis, the causal agent of periodontal infection, carry at least two types of fimbriae, namely FimA and Mfa1 fimbriae, following the names of their major subunit proteins. Normally, FimA fimbriae are long filaments that are easily detached from cells, whereas Mfa1 fimbriae are short filaments that are tightly bound to cells; however, in the absence of Mfa2 protein, the Mfa1 fimbriae are also very long and are not attached. Mfa2 and Mfa1 are associated with each other in whole P. gingivalis cells to the extent that Mfa2 is located on the cell surface and probably associated with Mfa1 fimbriae in such a way that it anchors the Mfa1 fimbriae to the cell surface and regulates Mfa1 filament length.