SUBUNIT NUMBER AND ARRANGEMENT IN ESCHERICHIA-COLI HEAT-LABILE ENTERO-TOXIN
SUBUNIT NUMBER AND ARRANGEMENT IN ESCHERICHIA-COLI HEAT-LABILE ENTERO-TOXIN
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DOI：
10.1128/iai.33.3.677-682.1981
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发表时间：
1981-01-01
影响因子：
3.1
通讯作者：
FINKELSTEIN, RA
中科院分区：
文献类型：
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作者：
GILL, DM;CLEMENTS, JD;FINKELSTEIN, RA
大肠杆菌不耐热肠毒素(LT)与霍乱毒素具有相同的亚基结构，即1个A亚基和5个B亚基。与双亚胺酯反应生成了所有可能的A5B：B，2B…5B和A，AB……A5B。分离得到的B组分类油菜素含有5个B亚基，具有一定的聚合倾向；与双亚胺酯共价连接成B…5B组分，含有少量的6B…10B等。2个独立制备的LT样品的亚基组成均为A5B；在十二烷基硫酸钠存在下，它们的B五聚体在聚丙烯酰胺凝胶电泳板上以不同的速度迁移，表明它们具有不同的构象。通过在50℃下孵育，可以将较快的(R)形式转化为扩散较慢的(C)形式。C单独或在37度。C和0.2M半乳糖，这是神经节苷脂GM1的末端糖，神经节苷脂GM1是LT的天然受体。霍乱毒素更像是R型而不是C型。
The E. coli heat-labile enterotoxin (LT) was found to have the same subunit structure as cholera toxin, i.e., 1 A subunit and 5 B subunits. Reaction with a bisimidate generated all the possible cross-linked derivatives of A5B: B,2B ... 5B and A, AB ... A5B. The isolated B component, coligenoid, contained 5 B subunits and showed some tendency to polymerize; with a bisimidate it became covalently connected into the set B ... 5B with lesser amounts of 6B ... 10B, etc. The subunit formulas of 2 independently prepared samples of LT were both proved to be A5B by cross-linking; their B pentamers migrated at different rates on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, indicating that they have different conformations. The faster (R) form could be converted to a diffuse slower (C) form by incubating it at 50.degree. C alone or at 37.degree. C with 0.2 M galactose, which is the terminal sugar of ganglioside GM1, the natural receptor for LT. Cholera toxin resembled the R form more than the C form of LT.