Fig. 1. XMAP215 is a long rod-shaped molecule. (A) Gallery of uni-directional shadowed images of XMAP215 selected from two different XMAP215 preparations. Samples were sprayed onto mica and shadowed with platinum/carbon as described in the Materials and Methods. Most molecules appeared relatively straight, but a significant number were bent (e.g. bottom row), suggesting that XMAP215 is a flexible molecule. Scale bar: 100 nm. (B) Corresponding SDS-PAGE gel of the peak glycerol fraction used for shadowing. A small fraction of the sample was proteolyzed; this is commonly observed with XMAP215. The positions of M_r markers are shown. (C) Histogram of XMAP215 length distribution. The lengths of individual XMAP215 molecules were measured from digitized EM negatives of uni-directional shadowed XMAP215. The mean XMAP215 length of 60 nm is marked with an arrow.