Fiber diffraction pattern from an oriented sol of potato virus X. This pattern was obtained at the BioCAT beam line at the Advance Photon Source, Argonne National Laboratory. The oriented sol was made using a combination of shearing forces, centrifugation, and high magnetic fields. Layer lines, including the first layer line, which had not previously been resolved, are marked (Parker, L., Kendall, A., and Stubbs, G. (2002) Surface features of potato virus X from fiber diffraction. Virology 300, 291-295).