BINDING OF HUMAN SERUM AMYLOID P-COMPONENT TO PHOSPHOCHOLINE

被引:18
作者
CHRISTNER, RB [1 ]
MORTENSEN, RF [1 ]
机构
[1] OHIO STATE UNIV,DEPT MICROBIOL,COLUMBUS,OH 43210
关键词
SERUM AMYLOID P-COMPONENT; PENTRAXIN; C-REACTIVE PROTEIN;
D O I
10.1006/abbi.1994.1451
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Human serum amyloid P-component (SAP) and C-reactive protein (CRP) are structurally similar pentraxins composed of five identical subunits in a disc-like configuration and display Ca2+-dependent binding reactivity to a variety of unrelated ligands. CRP is generally classified and defined as a phosphocholine (PC)-binding protein, whereas SAP is identified as a polysaccharide-binding protein. We examined the PC-binding activity of human SAP and compared it to human CRP since many of the biological activities of CRP are triggered upon PC-binding. SAP was able to bind to immobilized PC in a saturable, Ca2+-dependent manner but with lower avidity than CRP in direct competitive binding assays. The affinity of the binding of SAP to soluble [C-14]PC was slightly lower than the affinity of CRP; however, the valence of SAP was only one PC-binding site/pentraxin or 2/protein vs 5 such sites per CRP molecule. Both SAP and CRP displayed a similar binding preference for PC vs phosphoethanoiamine (PE). Two monoclonal antibodies (mAb) generated against the PC-binding site of SAP also reacted with the PC-binding site of CRP and inhibited PC-binding by both pentraxins. A mAb specific for the PC-binding site on CRP also inhibited SAP binding to PC. SAP was also recognized by two anti-idiotypic mAb that shared reactivity with the TEPC-15 PC-binding myeloma protein and the PC-binding site of CRP. Both pentraxins could be isolated from human serum by affinity chromatography on either PC- or PE-substituted agarose beads. The findings indicate that SAP is also a PC-binding protein. (C) 1994 Academic Press, Inc.
引用
收藏
页码:337 / 343
页数:7
相关论文
共 49 条
  • [1] AGRAWAL A, 1992, J BIOL CHEM, V267, P25352
  • [2] BALLOU SP, 1992, ADV INTERNAL MED, V37, P313
  • [3] CHRISTNER RB, 1994, J BIOL CHEM, V269, P9760
  • [4] HAMSTER FEMALE PROTEIN - A NEW PENTRAXIN STRUCTURALLY AND FUNCTIONALLY SIMILAR TO C-REACTIVE PROTEIN AND AMYLOID-P COMPONENT
    COE, JE
    MARGOSSIAN, SS
    SLAYTER, HS
    SOGN, JA
    [J]. JOURNAL OF EXPERIMENTAL MEDICINE, 1981, 153 (04) : 977 - 991
  • [5] DEBEER FC, 1982, IMMUNOLOGY, V45, P55
  • [6] ISOLATION OF HUMAN C-REACTIVE PROTEIN AND SERUM AMYLOID P COMPONENT
    DEBEER, FC
    PEPYS, MB
    [J]. JOURNAL OF IMMUNOLOGICAL METHODS, 1982, 50 (01) : 17 - 31
  • [7] FIBRONECTIN AND C4-BINDING PROTEIN ARE SELECTIVELY BOUND BY AGGREGATED AMYLOID-P COMPONENT
    DEBEER, FC
    BALTZ, ML
    HOLFORD, S
    FEINSTEIN, A
    PEPYS, MB
    [J]. JOURNAL OF EXPERIMENTAL MEDICINE, 1981, 154 (04) : 1134 - 1149
  • [8] DONG AC, 1994, J BIOL CHEM, V269, P6424
  • [9] DUCLOS TW, 1988, J IMMUNOL, V141, P4266
  • [10] DUCLOS TW, 1991, J BIOL CHEM, V266, P2167