L22 molecular architecture and life cycle of filamentous viruses

Po tato vi rus X (PVX) is a mem ber of the fam ily Alpha flexi viridae in the ge nus Potexvirus. It in fects sev eral sola na ceous crops in clud ing po tato (it can cause yield losses of up to 15% in some va ri et ies), to mato and to bacco. Symp toms pro duced by PVX are vari able, de pend ing on the strain and host plant. In gen eral, plants of ten do not ex hibit symp toms, but the vi rus can cause symp toms of mild mot tling, chlorosis, mo saic or de creased leaf size. It can be me chan i cally trans mit ted. PVX has a monopartite plus-sense sin gle stranded RNA ((+)ssRNA) of ap prox i mately 6.4 kb (Skryabin et al., 1988). PVX virions are flex i ble rods 515 nm long and 13.5 nm in di am e ter, con sist ing of ap prox i mately 1350 heli cally folded iden ti cal coat pro tein (CP) sub units and vi ral RNA packed be tween its turns (Tollin and Wilson, 1988). So far, only low-res o lu tion struc ture of PVX virion has been de ter mine pro vid ing lim ited in for ma tion about CPCP and CP-RNA in ter ac tions. The aim of this pro ject is (1) to de ter mine the near-atomic struc ture of Po tato vi rus X and CP-CP and CP-RNA in ter act ing amino ac ids and (2) to de fine the sur face ex posed re gions/loops and test them for pos si ble tol er ance of in serted pep tides. PVX struc ture and in ter act ing amino ac ids was an a lyzed using cryo-electron microscopy.