GTP and GDP bound Tubulin-RB3 Complexes

GTP-Tubulin:RB3 Stathmin-Like Domain Complex

Shown here is the T2R dimer with bound GTP (Red) to both α (yellow) and β (beige) subunits. The RB3-SLD is shown in magenta.

Superimposing the α1β1 moiety of the mth complex onto the α2β2
moiety viewed along their axis (below).

The structures differ locally in the neighborhood of the nucleotide. A loop movement in GTP-bound tubulin favors its recruitment to the ends of growing microtubules and facilitates its curved-to-straight transition, but this conversion has not proceeded yet. The data therefore argue for the conformational change toward the straight structure occurring as microtubule-specific contacts are established.

The Determinants That Govern Microtubule Assembly from the Atomic Structure of GTP-Tubulin. J. Mol. Biol. 2011 (PubMed)

3RYF (PDB)

GDP-Tubulin:RB3 Stathmin-Like Domain Complex



                        Shown here is the T2R dimer with

α subunit (yellow)
                        bound to GTP (Red) and the

β (beige) subunits
                        bound to GDP (Green).

                        Superimposing the α1β1 moiety of the mth complex onto
                        the α2β2 moiety viewed perpendicular
                        to their axis (below).

Whereas a structural GTP is always bound to the α subunit and the β monomer, for microtubule assembly ; hydrolysis of this nucleotide to GDP follows incorporation in the polymer. By contrast with their straight microtubular counterpart, protofilaments at the ends of disassembling microtubules or made from pure GDP-tubulin are curved

The Determinants That Govern Microtubule Assembly from the Atomic Structure of GTP-Tubulin. J. Mol. Biol. 2011 (PubMed)

3RYI (PDB)