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Binding site on human C‐reactive Protein (CRP) recognized by the Leukocyte CRP‐receptor
Author(s) -
Zen Qin,
Zhong Wangjian,
Mortensen Richard F.
Publication year - 1997
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(199701)64:1<140::aid-jcb16>3.0.co;2-p
Subject(s) - pentamer , peptide , receptor , chemistry , binding site , c reactive protein , microbiology and biotechnology , formyl peptide receptor , biochemistry , inflammation , biology , immunology , chemotaxis
C‐reactive protein (CRP), the prototypical inflammatory acute phase reactant in humans, interacts with monocytes and neutrophils via a specific receptor. To map the site on CRP recognized by the CRP receptor (CRP‐R), synthetic peptides corresponding to the surface region on each of the five identical subunits were tested as competitors vs. [ 125 l]‐CRP for cell binding. A peptide of residues 27–38 (TKPLKAFTVCLH) efficiently inhibited CRP binding when compared to other nonoverlapping peptides. This peptide was termed the cell‐binding peptide (CB‐Pep). The F(ab′) 2 of an IgG Ab to the CB‐Pep specifically inhibited CRP binding upon reacting with the ligand. Competitive binding studies with synthetic peptides truncated from either the NH 2 ‐ or COOH‐terminus of the CB‐Pep revealed that the minimum length recognized by the CRP‐R consisted of residues 31–36: KAFTVC. Conservative substitutions of residues within the CB‐Pep indicated that the four residues AFTV were critical for CRP‐R binding. The CB‐Pep also inhibited induced superoxide generation by HL‐60 granulocytes. The minimum length required for the inhibition was also KAFTVC; however, only Phe‐33 and Leu‐37 were critical residues in this assay. Anti‐CB‐Pep IgG Ab reacted more extensively with heat‐modified CRP, suggesting that an altered conformation of CRP is preferentially recognized by the CRP‐R. The results suggest that this contiguous sequence on a β‐strand on one face of each of five subunits of the CRP pentamer serves as a unique recognition motif for inflammatory leukocytes. J. Cell. Biochem. 64:140–151. © 1997 Wiley‐Liss, Inc.