Implications of the factor H/FHL-1 binding site. (a, b) Surface representations of dimers from PDB entries 1w33 and 4bl4, respectively, highlighting residues Lys136, Lys141, Lys143, Glu144 and Glu47 which have been shown to be involved in factor H/FHL-1 binding (Kraiczy et al., 2009). Differences in the dimensions of the cleft between the subunits are also shown. (c) Typical dimensions of a single SCR domain. This figure was generated using PyMOL (Schrödinger LLC).