FIGURE 1.

A, model structure of Bsp family proteins based on the proposed domain organization of other AgI/II polypeptides (8, 9). This comprises a stalk consisting of the α-helical A domain and the polyproline II (PPII) helical P domain, separating the V domain and the C-terminal domains. The C-terminal domain is followed by the LPXTG motif required for cell wall anchorage. B, amino sequence alignment of BspA, BspB, BspC, and BspD. Structural regions are colored as in A with amino acids conserved in all four proteins highlighted in black.