Direct incorporation of microtubule oligomers at high GTP concentrations.
Chick brain microtubule protein consists primarily of a mixture of MAP2:tubulin oligomers and dimeric tubulin. The assembly of this protein is described by a single pseudofirst-order reaction at 20 microM GTP, but by the summation of two pseudofirst-order reactions at 1 mM GTP. The protein contains two GTP-binding species, corresponding to the tubulin dimers and the oligomers, and conditions which alter the dimer: oligomer equilibrium, affect the kinetics of microtubule assembly. The results indicate that the oligomers are only direct assembly intermediates at high GTP concentrations.
D000818:Animals; D002645:Chickens; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D011506:Proteins / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism*
D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; D011506:Proteins; D014404:Tubulin; D006160:Guanosine Triphosphate