While crystal structures of other FReD-containing proteins, including ficolin-2, have revealed the presence of functional binding surfaces across which extended ligands may bind (11), for example, ficolin-2 binds 1,3-β-D-glucan, a molecular marker of fungal infection, across a 25-Å binding surface at the S3 and S4 binding sites (Fig. 7), an extended surface at S1 has not previously been identified. The gene discussed is FCN2; the disease is fungal infectious disease.