title: Membrane attack by complement.
abstract: Membrane attack by complement involves the self-assembly on membranes of five hydrophilic proteins (C5b, C6, C7, C8 and C9) to an amphiphilic tubular complex comprising approximately 20 subunits. The hydrophilic-amphiphilic transition of the precursor proteins is achieved by restricted unfolding and exposure of previously hidden hydrophobic domains. Restricted unfolding, in turn, is driven by high-affinity protein-protein interactions resulting in the formation of amphilic complexes. Circular polymerization of C9 to a tubular complex (poly C9) constitutes the molecular mechanism for transmembrane channel assembly and formation of ultrastructural membrane lesions.
mesh_terms: D000818:Animals; D001704:Biopolymers; D002462:Cell Membrane / Q000276:immunology*; D055598:Chemical Phenomena; D002621:Chemistry; D003167:Complement Activation; D003182:Complement C5 / Q000378:metabolism; D003183:Complement C6 / Q000378:metabolism; D003184:Complement C7 / Q000378:metabolism; D003185:Complement C8 / Q000378:metabolism; D003186:Complement C9 / Q000378:metabolism; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000378:metabolism*; D008956:Models, Chemical; D011487:Protein Conformation
chemical_list: D001704:Biopolymers; D003182:Complement C5; D003183:Complement C6; D003184:Complement C7; D003185:Complement C8; D003186:Complement C9; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins