Location of fibronectin binding sites in AAF type I and II.
Cartoon diagrams (left) and electrostatic potential assessable surfaces (right) of three major subunit polymers are shown. Positively charged residues interacting with fibronectin are drawn as sphere models. Arg40 in AAF/II is also involved in biofilm formation. Regions of positive surface potential are depicted in blue and negative potential in red (scale is from −4 to 4 kT/e). AAF/II contains two fibronectin binding surfaces: a continuous array of arginines 23, 40, and 44 and a repeated patch of lysines 66 and 72. In AAF/I, the basic residues concentrated at the interface between adjacent subunits. Seven lysine residues 51, 55, 73, 76, 78, 103 and 109 in this region are involved in fibronectin binding.