Figure 3.

TOG5 HR 0 is positioned to engage laterally associated αβ-tubulin subunits on the MT lattice. (A) Stu2 TOG1 bound to a curved (4FFB, left) and straight (modeled, right) αβ-tubulin heterodimer. A gap is formed when TOG1 is superimposed on straight αβ-tubulin (1JFF). (B) Msps TOG5 superimposed on both curved (left) and straight (right) αβ-tubulin using the Stu2 TOG1–αβ-tubulin complex structure as a guide. Although modeling suggests that TOG5 can engage curved αβ-tubulin–like Stu2 TOG1, slight architectural differences in TOG5 uniquely position it to better engage straight αβ-tubulin. (C) TOG1 is not predicted to make lateral αβ-tubulin contacts when superimposed on the MT lattice (left). In contrast, TOG4 HRs D–F (4Y5J, middle) and TOG5 HR 0 (right) are positioned to contact laterally associated tubulin on the neighboring protofilament (red boxes). Cartoon schematics are depicted at bottom.