Effect of heterologous expression of molecular chaperone DnaK from Tetragenococcus halophilus on salinity adaptation of Escherichia coli
Effect of heterologous expression of molecular chaperone DnaK from Tetragenococcus halophilus on salinity adaptation of Escherichia coli
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DOI：
10.1016/s1389-1723(03)90114-9
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发表时间：
2003-08-01
影响因子：
2.8
通讯作者：
Sonomoto, K
中科院分区：
文献类型：
--
作者：
Sugimoto, S;Nakayama, J;Sonomoto, K
对嗜盐嗜盐四球菌JCM5888的分子伴侣DNAK在体内和体外盐度条件下进行了表征。将dNAK基因克隆到表达载体中，转化到大肠杆菌中。在含有5%(0.86M)NaC l的Luria-Bertani培养基中，重组大肠杆菌获得的DNAK蛋白对变性乳酸脱氢酶的复性活性明显高于非嗜盐乳球菌。反之，嗜盐乳杆菌DNAK的过表达显著缩短了延长的滞后期，对最大生长量没有影响，而乳酸乳杆菌过表达则降低了最大生长量。盐胁迫增加了大肠杆菌细胞中蛋白质聚集体的数量，而盐生嗜盐菌DNAK的过表达则大大抑制了这种聚集。这些结果表明，异源过表达的嗜盐嗜盐杆菌DNAK通过其伴侣活性促进了大肠杆菌对盐度的适应。
Molecular chaperone DnaK of halophilic Tetragenococcus halophilus JCM5888 was characterized under salinity conditions both in vitro and in vivo. The dnaK gene was cloned into an expression vector And transformed into Escherichia coli. The DnaK protein obtained from the recombinant E. coli showed a significantly higher refolding activity of denatured lactate dehydrogenase than that from non-halophilic Lactococcus lactis under NaCl concentrations higher than I M. E. coli without the overexpression of DnaK exhibited a growth profile with a prolonged lag phase and suppressed maximum cell density in Luria-Bertani medium containing 5% (0.86 M) NaCl. On the contrary, the overexpression of T halophilus DnaK greatly shortened this prolonged lag phase with no effect on maximum growth, while that of L. lactis DnaK decreased maximum growth. The amount of protein aggregates was increased by salt stress in the E. coli cells, while this aggregation was greatly suppressed by the overexpression of T halophilus DnaK. These results suggest that heterologous overexpression of T halophilus DnaK, via its chaperone activity, promotes salinity adaptation of E. coli.