Humphreys S, Humphreys T, Sano J
J Supramol Struct. 1977;7(3-4):339-51. doi: 10.1002/jss.400070307.
Aggregation factor, the macromolecular complex which mediates species-specific aggregation of dissociated sponge cells, was isolated from several species, partially characterized, and visualized by electron microscopy. All factors were large fibrous complexes with a backbone and side chains or arms. In some factors, the backbone is linear. In others it is circular and the complex appears as a sunburst with arms extending like rays from the circle. The size and location of the polysaccharide chains have been studied using purified preparations of Microciona prolifera. "Sunbursts" treated with ethylenediaminetraacetate (EDTA) for 4 weeks at 0 degrees C dissociate into 3 protein- and polysaccharide-containing components. Sodium dodecyl sulfate does not cause the sunburst to dissociate nor does it inhibit dissociation in the presence of EDTA suggesting that dissociation is not due to hydrolytic enzymes. The dissociation products were fractionated on a 977-A pore size micropore glass column. Fifteen percent of the material is excluded and appears in the electron microscope as the central circle of the sunburst. Digestion of the circles with 10(-3) M dithiothreitol (DTT) and 0.5 mg/ml proteinase K for 72 h at 37 degrees C produces 2 polysaccharide chains of 65,000 and 6,000 daltons as fractionated and sized on a 233-A pore size micropore glass column using Pharmacia dextrans as standards. The included fractions of the EDTA-treated material are subunits of the arms which contain 70% of the polysaccharide. A single polysaccharide of 6,000 daltons as measured on 233-A size glass beads and Sephadex G-75 is released from these subunits by proteinase digestion. Pharmacia dextrans are used as standard on both columns. We calculate that there would be four 65,000-dalton chains and one hundred 6,000-dalton chains per circle and fifty 6,000-dalton chains per arm. The third component of the EDTA-treated preparation is partially included on the column. It appears as linear fibrils in the electron microscope and contains polydisperse polysaccharides of several-hundred-thousand daltons. It may be an impurity since there is apparently less than 1 of the large polysaccharide chains per sunburst.
聚集因子是一种介导解离的海绵细胞进行物种特异性聚集的大分子复合物，已从多个物种中分离出来，进行了部分特性鉴定，并通过电子显微镜进行了观察。所有的因子都是具有主干和侧链或臂的大型纤维状复合物。在某些因子中，主干是线性的。在其他因子中，主干是环状的，复合物呈现出一种日晕状，臂像光线一样从圆圈中延伸出来。利用提纯的多管海绵制剂对多糖链的大小和位置进行了研究。在0℃下用乙二胺四乙酸（EDTA）处理4周后的“日晕”分解为3种含蛋白质和多糖的成分。十二烷基硫酸钠不会导致日晕分解，在有EDTA存在的情况下也不会抑制分解，这表明分解不是由水解酶引起的。分解产物在孔径为977 - A的微孔玻璃柱上进行分级分离。15%的物质被排阻，在电子显微镜下呈现为日晕的中心圆圈。在37℃下用10⁻³M二硫苏糖醇（DTT）和0.5mg/ml蛋白酶K消化这些圆圈72小时，产生两条分子量分别为65,000和6,000道尔顿的多糖链，这是使用Pharmacia葡聚糖作为标准在孔径为233 - A的微孔玻璃柱上进行分级分离和测定大小的结果。经EDTA处理的物质中被保留的部分是臂的亚基，其中含有70%的多糖。通过蛋白酶消化从这些亚基中释放出一条在233 - A大小的玻璃珠和Sephadex G - 75上测定分子量为6,000道尔顿的单一多糖。在两根柱子上都使用Pharmacia葡聚糖作为标准。我们计算出每个圆圈有四条65,000道尔顿的链和一百条6,000道尔顿的链，每条臂有五十条6,000道尔顿的链。经EDTA处理的制剂的第三种成分部分被保留在柱上。它在电子显微镜下呈现为线性纤维，含有分子量为几十万道尔顿的多分散多糖。它可能是一种杂质，因为每个日晕中显然少于一条大的多糖链。
