One dominant binding site (70 kDa 6.5 pI protein) for bacterial cell wall peptidoglycan (PGN), a macrophage activator and polyclonal B cell mitogen, was demonstrated on mouse B and T lymphocytes and macrophages by photoaffinity cross-linking and two-dimensional polyacrylamide gel electrophoresis. This binding site was not present on erythrocytes. The binding was specific for polymeric PGN and was competitively inhibited by unlabeled PGN with IC50 = 48 μg/ ml (0.38 μm). The binding was partially inhibited by O-acetylated PGN monomers (IC50 = 469 μg/ml, 521 μM), dextran sulfate (IC50 = 1024 μg/ml, 124 μM), and (GlcNAc)3 (IC50 = 6.6 mg/ml, 10 mM), and was not inhibited by non-O-acetylated PGN monomers and dimers, muramyl dipeptide, PGN pentapeptide, GlcNAc, teichoic acid, protein A, and gelatin. The cell surface location of the 70-kDa PGN-binding protein was indicated by the ability of PGN to bind to this protein in intact metabolically inactive cells (at 4°C and in the presence of 0.1% NaN3) and by the ability to extract the 70-kDa PGN-binding protein from viable B lymphocytes by noncytotoxic concentration of n-octyl-β-D-glucopyranoside.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|State||Published - 1991|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology