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Southern rice black-streaked dwarf virus (SRBSDV) coat protein (P10) is the key protein required for viral transmission and host plant infection and is thus a promising target for anti-SRBSDV agent screening. In this study, P10 was obtained from Escherichia coli through cloning, expression, and purification. The antiviral agent Ningnanmycin was selected as control, and a series of antiviral compounds based on the structural scaffold of ferulic acid were analyzed. Size-exclusion chromatography analysis results showed that compound F27 can alter the aggregation of P10 proteins. Furthermore, fluorescence titration and microscale thermophoresis assay results indicated that F27 binds to P10 with K A of 5.75 × 10 5 M −1 and K D of 7.81 μM. The ligand- and receptor-based three-dimensional quantitative structure–activity analyses were performed to determine the requirements for the interaction between the carboxyl structures and P10s. On the basis of the obtained models and information, we provided insights regarding the design and optimization of novel molecules as anti-SRBSDV agents. [ABSTRACT FROM AUTHOR]

Tobacco mosaic virus (TMV) is an important plant virus that can cause considerable crop loss. Our group synthesized a series of enantiomeric α-aminophosphonate derivatives with high anti-TMV activities. The activity of ( R) -diphenyl-1-(4-methylbenzothiazole-2-amino)-1-(thiphene-2-yl)-methylphosphonate (Q- R ) was found to be superior to that of ( S) -diphenyl-1-(4-methyl benzothiazole-2-amino)-1-(thiphene-2-yl)-methylphosphonate (Q- S ). However, the mechanism for inhibition of the R -isomer (Q- R ) of infection activity is not clear. Thus, we studied the interactions between Q- R and Q- S and TMV by using TMV coat proteins (CP) as a potential target for fluorescence spectroscopy, isothermal titration calorimetry, microscale thermophoresis, and molecular docking. Arg90 was found to play a major role in the interaction of Q- R with TMV CP, as demonstrated by the interaction experiments and the results of molecular modeling. The substitution of arginine with glycine resulted in a mutant that was significantly less sensitive to Q- R . These results indicate that Q- R undermines the structural stability of the TMV R90G virus particle by binding with Arg90, eventually leading to the loss of the virus’ ability for infection. [ABSTRACT FROM AUTHOR]