Fig. 1.

Visualization of the Ufd1-Npl4 complex by cryo- and negative stain EM. (Left Top) Class averages of frozen, hydrated Ufd1-Npl4 complex (each class contains ≈20 aligned images). (Left Middle) Negatively stained Ufd1-Npl4 single particles labeled with NiNTA-nanogold particles directed to the C-terminal His₆-tag of Ufd1. One gold bead is present per complex (arrows). (Left Bottom) Ufd1-Npl4 was incubated with monoclonal IgGs directed against the N-terminal UT3 fragment of Ufd1. The antibody (indicated with a bracket) is binding the elongated particle close to its center (arrows). (Right) Average of 300 particles obtained by cryo-EM with superimposed density contours and a putative domain mapping. The protein is shown in white. (Scale bars: 5 nm.)