%0 Journal Article %A Radwan, Mostafa M. %A Wilson, H. R. %A Duncan, G. H. %T Diffraction Studies of Tulip Virus X Particles %D 1981 %J Journal of General Virology, %V 56 %N 2 %P 297-302 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-56-2-297 %K tulip virus X %K optical diffraction %K X-ray diffraction %K potexvirus %I Microbiology Society, %X SUMMARY X-ray diffraction from oriented tulip virus X (TVX) particles and optical diffraction from electron micrographs show that the virus particles have a helical structure with a pitch of about 3.25 nm and a true repeat in five turns of the helix. Both X-ray and optical diffraction indicate that the number of subunits in the repeat period is 5q + 4, where q is an integer. The X-ray diffraction patterns suggest that 9 ⩾ q ⩾ 6, and the optical diffraction patterns suggest that q is probably 7 or 8. The X-ray diffraction patterns indicate that there is a marked feature in the virus particle at a radial position of about 3.3 nm, which is probably the RNA. The equatorial diffraction further suggests that the virus has an axial hole of about 1.5 nm radius. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-56-2-297