Figure 5: Anti-phosphotyrosine Fab antibody distinguishes the intracellular side of the IP39 structures.
From: The four-transmembrane protein IP39 of Euglena forms strands by a trimeric unit repeat
(a,b) Projection maps merged from the non-tilted images of IP39 crystals (a) and IP39 crystals with Fab fragments of anti-phosphotyrosine antibody (b). Red arrows indicate the prominent disappearance of the lines of the projection densities with the addition of Fab. The black bars represent 40 Å. (c,d) Three-dimensional maps reconstituted from 0–45° images of IP39 crystals (grey mesh) and IP39 crystals with Fab fragments of anti-phosphotyrosine antibody (green surface) are superimposed. The resolution limits of the two maps are cutoff at 10 Å. The EM maps are viewed perpendicular (c, from the luminal side) and parallel (d) to the membrane plane. Red and black arrows indicate the regions of the bridge-like protrusion in strands A and B, respectively. The black bars represent 40 Å.
