产肠毒素大肠杆菌菌株膜的分离及肠毒素活性在不同亚细胞组分中的分布。

Isolation of the membranes of an enterotoxigenic strain of Escherichia coli and distribution of enterotoxin activity in different subcellular fractions.

作者信息

Wensink J, Gankema H, Jansen W H, Guinée P A, Witholt B

出版信息

Biochim Biophys Acta. 1978 Dec 4;514(1):128-36. doi: 10.1016/0005-2736(78)90082-2.

Abstract

The intracellular localization of enterotoxin in Escherichia coli AP1, a strain of porcine origin which produces high levels of heat-labile, but no heat-stable enterotoxin, has been examined. The cytoplasmic and outer membranes of this strain both contained enterotoxin activity, while the membranes isolated from a serologically related non-enterotoxigenic strain (E. coli AP2) also of porcine origin, did not show enterotoxin activity. The periplasmic fraction isolated from the enterotoxigenic strain contained considerable enterotoxin activity, but this activity was associated with outer membrane fragments present in the periplasmic fraction. Thus, of the total cellular enterotoxin activity, about 55%, 15% and 30% were present in the outer membrane, cytoplasmic membrane and the cell cytoplasm, respectively. The specific activity of enterotoxin was 20 units per mg protein in the cytoplasm and 90 and 150 units per mg protein in the cytoplasmic and outer membranes, respectively.

摘要

对猪源大肠杆菌AP1（一种产生高水平不耐热但不产生耐热肠毒素的菌株）中肠毒素的细胞内定位进行了研究。该菌株的细胞质膜和外膜均含有肠毒素活性，而从同样猪源的血清学相关非产肠毒素菌株（大肠杆菌AP2）分离的膜则未显示出肠毒素活性。从产肠毒素菌株分离的周质部分含有相当数量的肠毒素活性，但该活性与周质部分中存在的外膜片段有关。因此，在总的细胞肠毒素活性中，约55%、15%和30%分别存在于外膜、细胞质膜和细胞质中。细胞质中肠毒素的比活性为每毫克蛋白质20单位，细胞质膜和外膜中分别为每毫克蛋白质90单位和150单位。