Nucleotide specificity in microtubule assembly in vitro.
A procedure is described for removing most of the GDP bound at the exchangeable GTP binding site (E site) of tubulin. Microtubule protein containing substoichiometric amounts of GDP at the E site is found to polymerize in response to: (a) two nonhydrolyzable ATP analogues, adenylyl imidodiphosphate (AMP-PNP) and adenylyl beta, gamma-methylenediphosphonate (AMP-PCP); and (b) substoichiometric levels of GTP or dGTP. The results are interpreted as suggesting that: (1) when GDP is removed from tubulin, the E site shows broad specificity for nucleoside triphosphates: (2) microtubule assembly can be induced by the binding of substoichiometric amounts of nucleoside triphosphate to the E site.
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives; D000818:Animals; D001921:Brain; D006023:Glycoproteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D007700:Kinetics; D008870:Microtubules / Q000648:ultrastructure*; D009419:Nerve Tissue Proteins; D011485:Protein Binding; D013552:Swine; D014404:Tubulin
D006023:Glycoproteins; D009419:Nerve Tissue Proteins; D014404:Tubulin; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate