芽孢杆菌酰基高丝氨酸内酯酶基因的克隆及表达

Cloning and Expression of Genes encoding N-acylhomoserine Lactonase from Bacillus

N -酰基高丝氨酸内酯 (N -acyl-homoserinelactones,AHLs)作为细菌群体应答系统 (Quorum -sensing)中的关键信号分子 ,其浓度是决定许多动、植物病原菌致病基因的表达的关键因子。酰基高丝氨酸内酯酶基因可以水解AHLs分子的内酯键 ,使AHLs失去生物活性 ,从而减弱致病菌的危害。该研究旨在从芽孢杆菌中克隆酰基高丝氨酸内酯酶基因并获得纯化蛋白。根据已知酰基高丝氨酸内酯酶基因的保守序列设计引物 ,利用PCR方法从 2株芽孢杆菌的基因组DNA中克隆出两个基因SS1和SS10。利用在基因库中进行同源比对 ,结果表明SS1和SS10编码的蛋白产物SS1和SS10均为酰基高丝氨酸内酯酶。将两个基因在大肠杆菌中诱导表达 。

N-acylhomoserine lactones (AHLs),known as a key signal molecule in bacterial Quorum-sensing,are involved in the regulation of expression of pathogenic genes in several plant and human pathogenic bacteria.AHLase is able to inactivate AHL by cleave the ester bond of the homoserine lactone ring and therefore disrupt bacterial Quorum-sensing and attenuate the virulence of bacterial pathogens.The aim of this study is to clone genes encoding N-acylhomoserine lactones and express them in prokaryotic system.Two genes,namely SS1 and SS10,were cloned from Bacillus sp.SB4 and Bacillus thuringiensis serova shandongiensis respectively by PCR approach.The homology analysis revealed that SS1 and SS10 exhibited significant amino acid similarity with the known AHLases (AiiA) from other Bacillus strains and contained the conserved motif HXHXDH≈H≈D,indicating that both most likely encode AHLase.The fusion protein of SS1 and SS10 with GST were expressed in Escherichia coli and the purified proteins were recovered respectively.