Structure of a trimeric fragment of CL-K1 bound to a mannose disaccharide. A and B) top and side views. The carbohydrate is in white and Ca2+ in pink. Comparison of carbohydrate binding by C) CL-K1; D) mannan-binding lectin (PDB: 1KWY) and E) DC-SIGN (PDB: 2IT5). Polar interactions are shown by dotted lines. The penultimate sugar moiety (internal in a high-mannose oligosaccharide) is in grey. CL-K1, collectin-K1.