title: Structure and activation of C1: current concepts.
mesh_terms: D001665:Binding Sites; D003166:Complement Activating Enzymes / Q000378:metabolism; D003167:Complement Activation; D003172:Complement C1 / Q000378:metabolism*; D015922:Complement C1q; D015923:Complement C1r; D003173:Complement C1s; D006801:Humans; D008956:Models, Chemical; D011487:Protein Conformation
chemical_list: D003172:Complement C1; D015922:Complement C1q; D003166:Complement Activating Enzymes; D015923:Complement C1r; D003173:Complement C1s