Fig. 4. XMAP215 increases the width (A) and length (B) of partial tubulin rings. By contrast, XMAP215 does not change the radius of curvature of the protofilament rings (C). (D) A partial ring and the circle overlay used to measure the radius. The radius is shown in inches on the micrograph and was then converted to nm. For A,B, the means are denoted by arrows. Histograms are presented as the percent of the total sample falling within each range to compensate for differences in sample size.