PQR转运体基因赋予大肠杆菌BL21百草枯抗性

PQR Gene Conferring Paraquat Resistance to the Heterologous Host Escherichia coli

前期研究中成功地分离了2个对百草枯具有高度抗性的土壤细菌SPQ03和SPQ14。本研究从这两个菌分别克隆了基因PnPQR和OaPQR,二者ORF全长均为1 233 bp,编码410个氨基酸残基,含有11个跨膜区(TMS),属于非典型的主要易化超家族(major facilitator superfamily,MFS)。立体结构分析表明,蛋白的N端和C端分别由5个和6个由α-螺旋组成的跨膜区。只有P151L和P154V两个氨基酸不同。将两个基因在大肠杆菌BL21菌株中异源表达,能提高大肠杆菌对百草枯的抗性,但不能提高其对过氧化氢的抗性。

Paraquat is one of the most widely used herbicides in the world. There are 4 strains resistant to PQ. In this research, transporters PnPQR and OaPQR were cloned from SPQ03 and SPQ14. They respectively encode a 42.76 kD protein with 410 amino acids, containing 11 putative transmembrane domains, belongs to no typical major facilitator superfamily. Three-dimensional structure analysis showed that the protein N-terminal and C-terminal, respectively, were constituted 5 and 6 transmembrane domains consisted of a-helix, but two amino acids were different in local P151L and P154V. The engineering strain carried PnPQR or OaPQR gene was transformed into E. coli BL 21, and result showed that PnPQR or OaPQR engineering strains can increase resistance to paraquat, but it can not improve its resistance to hydrogen peroxide.