副溶血弧菌一种糖蛋白酶(复苏促进因子)在大肠杆菌中的表达及性质

Expression and Characterization of a Resuscitation-Promoting Factor Like Glycoprotease Gene from Vibrio parahaemolyticus

用PCR方法从副溶血弧菌8621.4基因组中扩增出1种细胞复苏促进因子家族的糖蛋白酶(Glycoprotease,Gcp)基因,核酸序列分析表明其含有完整的gcp基因开放阅读框,编码233个氨基酸组成的蛋白质。核酸序列与副溶血弧菌糖蛋白酶家族基因的序列相似性为100%。其氨基酸序列与哈维氏弧菌HY01、弧菌Ex25、溶珊瑚弧菌、拟态弧菌和杀鲑弧菌LFI1238等糖蛋白酶的序列相似性为67%～92%。将该基因克隆到表达载体pET28a,在大肠杆菌BL21(DE3)中诱导表达,用Ni琼脂糖亲和柱层析纯化的蛋白为单一条带,利用纯化的Gcp免疫新西兰大白兔制备特异性抗体,Western-Blotting分析发现正常生长及活的非可培养状态(VBNC)诱导过程中的副溶血弧菌细胞内表达的Gcp蛋白为1条带,分子量约为27kDa,而在VBNC状态的菌体中检测到2条蛋白带。研究结果为进一步探索海洋弧菌活VBNC的形成和复苏机制奠定基础。

A resuscitation-promoting factor like glycoprotease gene was cloned from the chromosomal DNA of pathogenic Vibrio parahaernolyticus 8621.4 by PCR amplification. The ORF of the glycoprotease gene consisted of 702 base pairs, encoding a polypeptide of 233 amino acids. The homologies of the nucleotide sequence with those of other V. parahaemolyticus stains were 100%. The similarities of the amino acid sequence with glycoproteases of gibrio harveyi HY01, Vibrio sp. Ex25, Vibrio coralliilyticus, Vib- rio mimicus and Vibrio salmonicida were from 67% to 92 %. The glycoprotease gene was then subcloned into pET28a and expressed in BL21 （DE3）. The polyclonal antibody was prepared by immunization of rabbits with the expressed protein, which was purified by Ni （＋）-affinity chromatography. A specific protein band of 27 kDa was detected in the whole-cell lysate preparation of normal cultural cells and 45 days culture cells of V. parahaemolyticus 8621.4 at low temperature conditions by western-blotting anal- ysis, and one additional band could be detected in the VBNC cells. These results may be of significance in evaluating the role of Gcp in entering into the VBNC state under starvation stresses and recovering from the VBNC state.