Paradis F W, Shareck F, Dupont C, Kluepfel D, Morosoli R
Centre de recherche en microbiologie appliquée, Institut Armand-Frappier, Laval, Québec, Canada.
Appl Microbiol Biotechnol. 1996 Jun;45(5):646-51. doi: 10.1007/s002530050742.
Streptomyces lividans IAF18, obtained by homologous cloning, is capable of over-producing XlnA. To investigate the possibility of the expression of foreign genes, various coding regions of the xylanase A gene (xlnA) were analysed. Expression/secretion vectors were constructed containing the regulatory elements of xlnA with the coding region of the leader peptide with or without the truncated structural gene encoding the first 310 amino acids of the XlnA. The genes coding for the Escherichia coli beta-glucuronidase and subunit 1 of the Bordetella pertussis toxin (S1) were used and their expression analysed. S. lividans transformants where the beta-glucuronidase gene was fused with the leader sequence produced up to 30 mg beta-glucuronidase/culture filtrate whereas only fused XlnA/S1 was detected and its yield was estimated to be 1 mg/1. The disappearance of the B. pertussis toxin S1 and beta-glucuronidase from the culture medium was due to the concomitant appearence of secreted proteases from S. lividans.
通过同源克隆获得的淡紫灰链霉菌IAF18能够过量产生木聚糖酶A（XlnA）。为了研究外源基因表达的可能性，对木聚糖酶A基因（xlnA）的各个编码区进行了分析。构建了表达/分泌载体，其包含xlnA的调控元件以及带有或不带有编码XlnA前310个氨基酸的截短结构基因的前导肽编码区。使用了编码大肠杆菌β-葡萄糖醛酸酶和百日咳博德特氏菌毒素亚基1（S1）的基因，并对它们的表达进行了分析。在淡紫灰链霉菌转化体中，β-葡萄糖醛酸酶基因与前导序列融合时，每培养滤液可产生高达30毫克的β-葡萄糖醛酸酶，而仅检测到融合的XlnA/S1，其产量估计为1毫克/升。百日咳博德特氏菌毒素S1和β-葡萄糖醛酸酶从培养基中的消失是由于淡紫灰链霉菌分泌的蛋白酶同时出现所致。
