P1 peptidase of Pea seed-borne mosaic virus contains non- canonical C2H2 zinc finger and may act in a truncated form

Background: Pea seed-borne mosaic virus (PSbMV) is a member of the genus Potyvirus that can be transmitted by seeds, causing serious losses in legume crop yields. Its genome consists of 3 peptidases-P1, HC-Pro, and NIa. Interestingly, only the P1 peptidase, localized on the N-terminal portion of the viral polyprotein, still remains without any concrete function on influencing viral infections. Results: P1 peptidase consists of the originally-described C2H2 zinc finger motif. This newly revealed characteristic can help further clarify its true activity during viral infection. The truncated portion of P1 (Δ33-143) was expressed in bacteria and used for production of polyclonal antibody in rabbit. Using this antibody, it was shown that P1 (42 kDa) can be presented in infected plant also in a shorter form (30 kDa). Immunocytochemical localization of P1 in the protoplasts, obtained from the infected pea plant, demonstrated the localization of P1 in the cytoplasm, as well as in the nucleus. Moreover, newly found C2H2 motive can form active cavity according to in silico model of P1 molecule. Conclusions: Herein, it was described the C2H2 zinc finger motif (ZnF), which is non-standard compared to others present in the eukaryotic world. Moreover, the predicted protein models in silico of the ZnF found. Similar ZnF was also found in the P1 of another 5 viruses (3 Potyviruses, and 2 Tritimoviruses).