Structural aspects and design of low-molecular-mass complement inhibitors.

We present a mini-review on the structure-based design of three promising complement inhibitors. Firstly, we review compstatin, a 13-residue cyclic peptide that binds to C3 and inhibits the cleavage of C3 to C3a and C3b. Secondly, we review a six-residue cyclic peptide that binds to C5aR and antagonizes the binding of C5a to its receptor C5aR. Finally, we review three small molecules that bind to Factor D and inhibit the enzymic action of Factor D, during which Factor D proteolytically cleaves Factor B in complex with C3 or C3b.