title: Comparative structural anatomy of the complement anaphylatoxin proteins C3a, C4a and C5a.
abstract: The anaphylatoxins are a family of proteins produced during the course of complement activation as the result of cleavage by specific serine proteases. These proteins are involved in a variety of biological functions, including inflammation. Comparative modeling techniques have been used to produce structures for C4a and C5a from the crystal structure of C3a. All three structures have conserved interior residues but very different external side chains and surface shapes and properties. Comparison of the anaphylatoxin structures and of the sequence conservation among different species suggests possible locations for their receptor binding sites and for their specificity residues which permit regulated proteolytic cleavage from precursor.
mesh_terms: D000595:Amino Acid Sequence; D000706:Anaphylatoxins; D003176:Complement C3; D015926:Complement C3a; D003181:Complement C4; D015934:Complement C4a; D003182:Complement C5; D015936:Complement C5a; D003196:Computer Graphics; D008958:Models, Molecular; D010455:Peptides; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D000706:Anaphylatoxins; D003176:Complement C3; D003181:Complement C4; D003182:Complement C5; D010455:Peptides; D015926:Complement C3a; D015934:Complement C4a; D015936:Complement C5a