Landale E C, McCabe M M
Department of Microbiology and Immunology, University of Miami School of Medicine, Florida 33101.
Infect Immun. 1987 Dec;55(12):3011-6. doi: 10.1128/iai.55.12.3011-3016.1987.
Glucan-binding protein 1 (GBP1), the most abundant glucan-binding protein isolated from culture supernatants of Streptococcus sobrinus 6715-49, has been purified by affinity chromatography on Sephadex G-50 followed by gel permeation chromatography with Bio-Gel P-10. The specificity and affinity of GBP1 for glucans were assessed by affinity electrophoresis. GBP1 did not detectably bind to glucans lacking linear arrays of alpha-1,6 linkages. The association constant for the linear alpha-1,6-glucan Dextran T2000 was 3 x 10(7) M-1. Providing small isomaltosaccharide ligands to compete with this dextran indicated that the binding site maximally accommodated isomaltosaccharides with a degree of polymerization of 8. When glucans produced by purified S. sobrinus glucosyltransferases were tested, GBP1 displayed the highest affinity for the glucan from the soluble-product, primer-independent glucosyltransferase.
葡聚糖结合蛋白1（GBP1）是从远缘链球菌6715 - 49培养上清液中分离出的最丰富的葡聚糖结合蛋白，通过在葡聚糖凝胶G - 50上进行亲和层析，随后用生物凝胶P - 10进行凝胶渗透层析进行纯化。通过亲和电泳评估GBP1对葡聚糖的特异性和亲和力。GBP1未检测到与缺乏α-1,6键线性排列的葡聚糖结合。线性α-1,6 - 葡聚糖葡聚糖T2000的缔合常数为3×10⁷ M⁻¹。提供小的异麦芽糖低聚糖配体与这种葡聚糖竞争表明，结合位点最大程度地容纳聚合度为8的异麦芽糖低聚糖。当测试由纯化的远缘链球菌葡糖基转移酶产生的葡聚糖时，GBP1对来自可溶性产物、不依赖引物的葡糖基转移酶的葡聚糖显示出最高亲和力。
