Dziarski R, Gupta D
Northwest Center for Medical Education, Indiana University School of Medicine, Gary 46408.
J Biol Chem. 1994 Jan 21;269(3):2100-10.
The same 70-kDa protein, present on the surface of mouse lymphocytes, served as the predominant binding site for heparin, heparinoids, and bacterial lipoteichoic acids, as well as peptidoglycan and lipopolysaccharides. This conclusion was supported by the following results: (a) all of these compounds photoaffinity cross-linked to one major 70-kDa 6.5-7.0 pI protein that co-migrated on two-dimensional polyacrylamide gel electrophoresis; (b) peptide maps of the 70-kDa proteins digested with chymotrypsin, subtilisin, protease V, or papain yielded the same peptides for heparin-, lipoteichoic acid-, peptidoglycan-, and lipopolysaccharide-binding proteins; (c) cross-linking of peptidoglycan, lipopolysaccharide, lipoteichoic acid, and heparin was competitively inhibited by the same compounds with the same order of potency, i.e. carboxyl-reduced sulfated heparin > peptidoglycan > pentosan polysulfate > heparin > chitin > dextran sulfate > trestatin sulfate > polyanetholesulfonate > fucoidan > beta-cyclodextrin tetradecasulfate > heparan sulfate > carrageenan lambda > lipoteichoic acids > Re-lipopolysaccharide > lipopolysaccharide > lipid A > polygalacturonic acid; and (d) cross-linking of each of these ligands was not inhibited by carboxyl-reduced heparin, dextran, beta-cyclodextrin, trestatin, carrageenan kappa, chondroitin 4-sulfate, chondroitin 6-sulfate, beta-D-glucan, carboxy-methylcellulose, levan, alpha-D-mannan, and glycogen. The minimum size of the molecule that bound was 7-9 glycan residues, whereas, di- and trisaccharides did not bind. There was a logarithmic linear relationship between the strength of the binding and the length of the polymer (up to > 1500 glycan residues), which indicates an avidity effect of the cooperative binding of one polymeric molecule to several receptor molecules on the cell surface. The 70-kDa receptor, therefore, has a broad, but limited specificity of binding for non-charged (peptidoglycan and chitin), highly negatively charged (heparin and heparinoids), and weakly negatively charged (lipoteichoic acids, lipopolysaccharides, and lipid A) ligands.
存在于小鼠淋巴细胞表面的同一种70 kDa蛋白，是肝素、类肝素、细菌脂磷壁酸以及肽聚糖和脂多糖的主要结合位点。以下结果支持了这一结论：(a) 所有这些化合物通过光亲和交联到一种主要的70 kDa、pI为6.5 - 7.0的蛋白上，该蛋白在二维聚丙烯酰胺凝胶电泳上共迁移；(b) 用胰凝乳蛋白酶、枯草杆菌蛋白酶、蛋白酶V或木瓜蛋白酶消化70 kDa蛋白得到的肽图谱，对于肝素、脂磷壁酸、肽聚糖和脂多糖结合蛋白产生相同的肽段；(c) 肽聚糖、脂多糖、脂磷壁酸和肝素的交联被相同的化合物以相同的效力顺序竞争性抑制，即羧基还原硫酸化肝素>肽聚糖>戊聚糖多硫酸盐>肝素>几丁质>硫酸葡聚糖>曲格列汀硫酸盐>聚苯乙烯磺酸盐>岩藻依聚糖>β-环糊精十四硫酸盐>硫酸乙酰肝素>卡拉胶λ>脂磷壁酸>Re-脂多糖>脂多糖>脂质A>聚半乳糖醛酸；(d) 这些配体中的每一种的交联都不被羧基还原肝素、葡聚糖、β-环糊精、曲格列汀、卡拉胶κ、硫酸软骨素4-硫酸盐、硫酸软骨素6-硫酸盐、β-D-葡聚糖、羧甲基纤维素、果聚糖、α-D-甘露聚糖和糖原抑制。结合的分子的最小大小为7 - 9个聚糖残基，而二糖和三糖不结合。结合强度与聚合物长度（直至>1500个聚糖残基）之间存在对数线性关系，这表明一个聚合物分子与细胞表面上的几个受体分子协同结合的亲合力效应。因此，70 kDa受体对不带电荷的（肽聚糖和几丁质）、高度带负电荷的（肝素和类肝素）以及弱带负电荷的（脂磷壁酸、脂多糖和脂质A）配体具有广泛但有限的结合特异性。
