ИСТИНА

Previously we demonstrated that deletions in the intrinsically disordered C-terminus of TMV CP dramatically affected viral infection: deletions more then 3 amino acid residues (a.a) (CPΔPAT), namely 6 a.a. (CPΔTSG) and 20 a.a. (CPΔYNR) abolished viral infection. In this work we studied structural characteristics of the recombinant CPs and their ability to interact with TMV movement protein (MP). We used circular dichroism (CD) spectroscopy in the far UV region to compare optical properties of recombinant CPs and showed that deletion of even 3 C-terminal a.a. (CPΔPAT) led to the serious structural rearrangements of the TMV CP molecule, accompanied by a transition of alpha-structural protein (wild type TMV CP) into protein with an increasing number of beta elements. Deletions in the CP C-terminus also changed surface charge (zeta potential) and increased aggregation ability of mutant CPs. The wt TMV CP and CPΔPAT but not CPΔTSG and CPΔYNR were able to interact with TMV MP in vitro (Far-Western assay). These data are in agreement with the results obtained in vivo during simultaneous agroinfiltration constructs expressing genes of GFP-MP and mRFP-CP into leaves of Nicotiana benthomiana plants. Both proteins were colocalized in cell wall plasmodesmata. We suggest that the TMV CP C-terminus contains functional determinant/determinants involved in previously assumed interaction with TMV MP and cell-to-cell transport and likely takes part in virion assembly. This work was supported by the Russian Science Foundation project No 14-24-00007.