Title : Structure-function analysis of the extracellular
domains of the
Duffy antigen/receptor for chemokines : characterization of antibody and chemokine binding
sites
Abstract :
- The Duffy antigen/receptor for chemokines ( DARC ), a seven-transmembrane glycoprotein carrying the Duffy (Fy) blood group, acts as a widely expressed promiscuous chemokine receptor
- In a structure-function study, we analysed the binding of chemokines and anti-Fy monoclonal antibodies (mAbs) to K562 cells expressing 39 mutant forms of DARC with alanine substitutions spread out on the four extracellular domains (ECDs)
- Using synthetic peptides , we defined previously the Fy6 epitope (22-FEDVW-26), and we characterized the Fya epitope as the linear sequence 41-YGANLE-46
- In agreement with these results, mutations of F22-E23, V25 and Y41, G42, N44 , L45 on ECD1 abolished the binding of anti-Fy6 and anti-Fya mAbs to K562 cells respectively, Anti-Fy3 binding was abolished by D58-D59 ( ECD1 ), R124 (ECD2), D263 and D283 (ECD4) substitutions
- Mutations of C51 (ECD1 ), C129 (ECD2), C195 (ECD3) and C276 (ECD4 severely reduced anti-Fy3 and CXC-chemokine ligand 8 8 (CXCL-8 ) binding
- CXCL-8 binding was also abrogated by mutations of F22-E23, P50 ( ECD1 ) and D263, R267, D283 (ECD4)
- These results defined the Fya epitope and suggested that (1) two disulphide bridges are involved in the creation of an active chemokine binding pocket; (2) a limited number of amino acids in ECDs 1-4 participate in CXCL-8 binding; and (3) Fy3 is a conformation-dependent epitope involving all ECDs
- We also showed that N-glycosylation of DARC occurred on N16SS and did not influence antibody and chemokine binding
Output (sent_index, trigger,
protein,
sugar,
site):
- 1. glycoprotein, , Duffy antigen/receptor for chemokines, -, -
- 1. glycoprotein, , glycoprotein, -, -
- 8. N-glycosylation, , DARC, -, -
Output(Part-Of) (sent_index,
protein,
site):
- 0. Duffy antigen/receptor for chemokines, domains
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):