Prokaryotic Expression And Purification Of The Coat Protein Of Southern Rice Black-streaked Dwarf Virus And Its Interaction With Antiviral Agents

In recent years,Southern rice black-streaked dwarf virus(SRBSDV)seriously reduced rice production in southern China.However,due to the lack of effective anti-SRBSDV agents at present and the existing anti-SRBSDV agent mechanism of actvity is unclear.SRBSDVcoat protein(P10)is the key protein required for viral transmission as well as infection in host plant and is thus a promising target for anti-SRBSDV agent screening.It was reported that ferulic acid and its derivatives had agricultural activity,which had good inhibitory activity against Rice black dwarf virus,Tomato virus,Potato virus,Melon virus and Maize dwarf mosaic virus.It was a potential anti-SRBSDV Pharmacy.In this study,the SRBSDV P10 protein was obtained by cloning,expression and purification.The interaction between SRBSDV P10 and antiviral agents was studied by fluorescence spectroscopy and microscale thermophoresis.The affinity between antiviral drugs and SRBSDV P10 was selected to evaluate the antiviral activity and a drug screening model based on SRBSDV P10 was established.A series of antiviral compounds based on the structural scaffold of ferulic acid were analyzed.The results showed that there was no interaction between antiviral agents(dufulin,amino oligosaccharides,lentinan,morpholine guanidine hydrochloride,ribavirin)and SRBSDV P10 protein.NNM showed strong binding to SRBSDV P10,the affinity KA=6.17×105 M-1.A further study of SEC found that NNM could destroy the aggregation state of SRBSDV P10 in solution.KA,the binding constant of F27 to SRBSDV P10 was 5.75×105 M-1.Using Comparative molecular field analysis(CoMFA)and comparative molecular similarity index analysis(CoMSIA)methods,the 3D-QSAR model was constructed by Sybyl X-2.0 software based on the KA values of 34 ferulic acid derivatives binding to SRBSDV P10.The q2 were 0.544 and 0.692,repectively,which were greater than 0.5 so that the model had a reliable ability to predict.The results of the FT assay and 3D-QSAR analysis showed that the affinity of SRBSDV P10 was enhanced by the retention of ferulic acid carboxyl structure and the introduction of a small steric hindrance at the R2 position.