title: Roles of nucleoside triphosphates in microtubule assembly.
abstract: Depolymerization of microtubules in the ATP-reassembly buffer permitted the preparation of GDPETNGTP. Incubation of this tubulin fraction at 35 degrees with ATP induced the phosphorylation of E-site GDP into GTP, which was then dephosphorylated during microtubule assembly. Incubation of GDPETNGTP with phosphoenolpyruvate and pyruvate kinase [EC 2.7.1.40] also induced polymerization. Depolymerization of microtubules in the GTP-reassembly buffer yielded GTPETNGTP, which was capable of polymerizing into microtubules even in the absence of free GTP. In the presence of 4 M glycerol, GDPETNGTP assembled into microtubules with no change in the bound nucleotides.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D006150:Guanine Nucleotides / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D011131:Polyribonucleotides / Q000096:biosynthesis; D011485:Protein Binding; D012265:Ribonucleotides / Q000378:metabolism*; D013552:Swine; D014404:Tubulin / Q000378:metabolism
chemical_list: D006150:Guanine Nucleotides; D011131:Polyribonucleotides; D012265:Ribonucleotides; D014404:Tubulin; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate