Courtney H S, Simpson W A, Beachey E H
J Bacteriol. 1983 Feb;153(2):763-70. doi: 10.1128/jb.153.2.763-770.1983.
The ability of Streptococcus pyogenes lipoteichoic acid and palmitic acid to bind to purified human plasma fibronectin was investigated. Initial studies indicated that intact fibronectin formed soluble complexes with lipoteichoic acid, resulting in a change in the mobility of fibronectin in an electrical field. Fibronectin covalently linked to agarose beads bound radiolabeled lipoteichoic acid in the acylated form but not in the deacylated form. An 18-M excess of fibronectin inhibited binding of lipoteichoic acid to the immobilized protein by 92%. Fibronectin-bound [(3)H]lipoteichoic acid could be specifically eluted with unlabeled lipoteichoic acid, as well as by fatty acid-free serum albumin. Serum albumin, which is known to contain fatty acid-binding sites capable of binding to the lipid moieties of lipoteichoic acid, inhibited the binding of lipoteichoic acid to fibronectin in a competitive fashion. The fibronectin-bound lipoteichoic acid could be eluted by 50% ethanol and various detergents but not by 1.0 M NaCl, various amino acids, or sugars. Similarly, radiolabeled palmitic acid adsorbed to fibronectin could be eluted with 50% ethanol but not with 1.0 M NaCl. Fibronectin adsorbed to a column of palmityl-Sepharose was eluted with 50% ethanol in 0.5% sodium dodecyl sulfate but not with 1.0 M NaCl or 1% sodium dodecyl sulfate alone. The binding of lipoteichoic acid to fibronectin followed first-order kinetics and was saturable. A Scatchard plot analysis of the binding data indicated a heterogeneity of lipoteichoic acid-binding sites similar to that previously found for serum albumin. Nevertheless, fibronectin contains at least one population of high-affinity binding sites for lipoteichoic acid. The binding affinity (nKa approximately 250 muM(-1)) is 2 orders of magnitude greater than the binding affinity of serum albumin. These data suggest that human plasma fibronectin contains specific binding sites for fatty acids and that lipoteichoic acid binds to these sites by way of its glycolipid moiety.
研究了化脓性链球菌脂磷壁酸和棕榈酸与纯化的人血浆纤连蛋白结合的能力。初步研究表明，完整的纤连蛋白与脂磷壁酸形成可溶性复合物，导致纤连蛋白在电场中的迁移率发生变化。与琼脂糖珠共价连接的纤连蛋白结合酰化形式而非脱酰化形式的放射性标记脂磷壁酸。18倍过量的纤连蛋白可使脂磷壁酸与固定化蛋白的结合减少92%。纤连蛋白结合的[(3)H]脂磷壁酸可用未标记的脂磷壁酸以及无脂肪酸的血清白蛋白特异性洗脱。已知含有能够结合脂磷壁酸脂质部分的脂肪酸结合位点的血清白蛋白，以竞争方式抑制脂磷壁酸与纤连蛋白的结合。纤连蛋白结合的脂磷壁酸可用50%乙醇和各种去污剂洗脱，但不能用1.0 M NaCl、各种氨基酸或糖类洗脱。同样，吸附在纤连蛋白上的放射性标记棕榈酸可用50%乙醇洗脱，但不能用1.0 M NaCl洗脱。吸附在棕榈酰-琼脂糖柱上的纤连蛋白用含0.5%十二烷基硫酸钠的50%乙醇洗脱，但不能用1.0 M NaCl或单独的1%十二烷基硫酸钠洗脱。脂磷壁酸与纤连蛋白的结合遵循一级动力学且具有饱和性。对结合数据的Scatchard图分析表明，脂磷壁酸结合位点具有异质性，类似于先前在血清白蛋白中发现的情况。然而，纤连蛋白至少含有一群对脂磷壁酸具有高亲和力的结合位点。结合亲和力（nKa约为250 μM(-1)）比血清白蛋白的结合亲和力高2个数量级。这些数据表明，人血浆纤连蛋白含有脂肪酸特异性结合位点，脂磷壁酸通过其糖脂部分与这些位点结合。
