Preliminary judgment of the antibacterial functions of two recombinant WSSV envelope proteins VP281 and VP31

Abstract

In order to understand the functions of white spot syndrome virus(WSSV) envelope proteins VP281 and VP31,the method of prokaryotic expression was used in this study.By using a prokaryotic constitutive secretory expression plasmid pBTA1 as the expression vector,the recombinant Escherichia coli strain DH5α that could constitutively secrete WSSV envelope protein rVP281,rVP28 or the fusion protein of VP28 and the enhanced green fluorescence protein rEGFP were constructed.They were respectively named as DhpVP281,DhpVP28 and DhpVP28-EGFP.The three recombinant bacteria were cultured on the LB plates in the same condition and their clone diameters were respectively(164.84±28.44) μm,(560.47±46.04) μm and(548.21±58.54) μm when cultured for 12 hours,(436.31±47.56) μm,(1136.90±110.88) μm and(1083.33±109.83) μm when cultured for 19 hours and(594.19±57.17) μm,(1251.19±188.86) μm and(1264.29±172.78) μm when cultured for 24 hours.It was displayed that the clones of DhpVP281 were significantly smaller than those of DhpVP28 and DhpVP28-EGFP in the whole culturing period(P0.05) and we guessed that the expression of rVP281 probably inhibited the growth of E.coli.However,recombinant bacteria constitutively expressing VP31 can not be constructed with the vector pBTA1.In order to find out the reason,recombinant bacteria BL21(DE3) pLysS were constructed with pET-30a(+) as the expression vector and rVP31 was obtained in the form of inclusion body.After renaturation,the antibacterial activity of rVP31 was tested.The result showed that rVP31 has the antibacterial activity against Micrococcus lysodeikticus.These findings,reported for the first time,may increase the virology knowledge of WSSV.