FIG. 5.

Electron microscopy of TrwK oligomers. Protein eluted from a size exclusion chromatography column (GL 10/30 Superdex200) at an MW_app of ∼500 (indicated by the asterisk in panel A; insert, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of fractions from the chromatogram) were stained with uranyl acetate and analyzed by electron microscopy (B; scale bar, 50 nm). Particles (4,907) were selected, aligned, and classified by maximum likelihood multireference alignment methods. Three of the class averages (200 to 300 particles) are represented in panel C (scale bar, 5 nm).