ABSTRACT
The Rice Yellow Mottle sobemovirus (RYMV) belongs to the most damaging pathogens devastating rice fields in Africa. P1, a key protein for RYMV, was reported as a potent RNAi suppressor counteracting RNA silencing in plant reporter systems. Here we describe the complete 3D structure and dynamics of P1. Its N-terminal region contains ZnF1, a structural CCCC-type zinc finger strongly affine to zinc and a prominent short helix, rendering this region poorly amenable to structural changes. P1 C-terminal region contains ZnF2, an atypical HCHC-type ZnF that does not belong to any existing class of Zn finger proteins. ZnF2 appeared much less affine to zinc and more sensitive to oxidizing environments than ZnF1, and may serve as a sensor of plant redox status. The structure helped us to identify key residues essential for RYMV infectivity and spread in rice tissues through their participation in P1 oligomerization and folding. Altogether, our results provide the first complete structure of an antiviral silencing suppressor encoded by a virus infecting rice and highlight P1 structural and dynamical properties that may serve RYMV functions to infect and invade its host plant.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
In the new version of the manuscript by Poignavent and co-authors, the following items have been added: -Running title -list of keywords The following minor modifications have also been added: -the name of Kim JH in the authors list has been corrected -The last sentence of the abstract has been modified -Figure 4: the design of panels C and D has been slightly modified -Appendix Table 1 : pESZ vector names and related primers for cloning have been added -Additional information regarding immunoblotting has been placed in Materials and methods sections