Generation of chimeric C5a/formyl peptide receptors: towards the identification of the human C5a receptor binding site.
We employed the polymerase chain reaction to produce a series of chimeric C5a/formyl peptide receptors. Chinese hamster ovary cells transfected with these constructs were tested for their ability to bind C5a. Substitution of three of the extracellular domains of the C5a receptor with the corresponding domains of the formyl peptide receptor abolished C5a binding, whilst replacement of the first extracellular loop of the C5a receptor with that of the formyl peptide receptor had little effect on the affinity of the receptor for C5a. We therefore conclude that this first outer loop of the C5a receptor does not participate in ligand binding, whilst involvement of the other extracellular domains of the receptor cannot be ruled out.
Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, GB.
J E
JE
Pease
D R
DR
Burton
M D
MD
Barker
D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D015936:Complement C5a / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D004274:DNA, Recombinant; D006801:Humans; D008969:Molecular Sequence Data; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000096:biosynthesis* / Q000737:chemistry*; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000096:biosynthesis*; D018000:Receptors, Peptide / Q000096:biosynthesis*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis*; D014162:Transfection; D014169:Transformation, Bacterial
D004274:DNA, Recombinant; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D018000:Receptors, Peptide; D011993:Recombinant Fusion Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015936:Complement C5a