Abstract: 【Objective】In order to confirm the function of vpr gene. 【Method】 The complement of the mutant strain MC1061△vpr was constructed by translating intact vpr into the vpr isogenic knockout E. coli mutant and identified using PCR. The lytic susceptibility of VT2 bacteriophage C43b to parent strain MC1061, mutant strain MC1061△vpr, complemented strain were detected. The cell walls of above three strains were extracted, respectively. The test of phage-adsorption to cell wall, Vpr protein expression and blotting were also carried out. 【Result】 One complemented strain, named MC1061-C, was obtained. The complemented strain returned the susceptibility to the lytic infection of VT2 phage with many small plaques, while the mutant was still resistant the phage. Phage-adsorption test within 30 min showed that 94.8% VT phage could adsorb on the cell walls of complemented MC1061-C, while 85.4％ VT phage could not adsorb on the cell walls of mutant MC1061△vpr. The specific peptide of 90 000 from parent and complemented strain were displayed by the Western blot using the rabbit anti-Vpr, the His-Vpr was purified by affinity chromatography. The mutant did not display this protein. 【Conclusion】All these revealed that the Vpr supported infection of VT2 phage and most likely be the receptor of VT2 phage.

Key words: Bacteriophage lytic, Susceptibility, Adsorption on cell walls, Western blot, Receptor