Figure 6. Comparison of donor-strand complementation by CfaB with that proposed by CfaA.

Six hydrophobic pockets are shown in the donor-strand binding groove of the electrostatic potential surface of the pilin subunit CfaB in the absence of donor strand. The six pockets are sequentially labeled from P0 to P5. The structure of the CfaA donor strand as determined in this work is given to the left of the CfaB surface, whereas that of CfaB is shown on the right based on the donor-strand complemented CfaB structure [17]. Residues that are presumed to fit into these pockets are also indicated.