Structure of human desArg-C5a.
The anaphylatoxin C5a is derived from the complement component C5 during activation of the complement cascade. It is an important component in the pathogenesis of a number of inflammatory diseases. NMR structures of human and porcine C5a have been reported; these revealed a four-helix bundle stabilized by three disulfide bonds. The crystal structure of human desArg-C5a has now been determined in two crystal forms. Surprisingly, the protein crystallizes as a dimer and each monomer in the dimer has a three-helix core instead of the four-helix bundle noted in the NMR structure determinations. Furthermore, the N-terminal helices of the two monomers occupy different positions relative to the three-helix core and are completely different from the NMR structures. The physiological significance of these structural differences is unknown.
Cook
William J
WJ
University of Alabama at Birmingham, Birmingham, AL 35294, USA. wjcook@uab.edu
Galakatos
Nicholas
N
Boyar
William C
WC
Walter
Richard L
RL
Ealick
Steven E
SE
D015937:Complement C5a, des-Arginine / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D044087:Receptor, Anaphylatoxin C5a / Q000737:chemistry / Q000378:metabolism
D015937:Complement C5a, des-Arginine; D044087:Receptor, Anaphylatoxin C5a