Carlier M F
Laboratoire d'Enzymologie, CNRS 91190 Gif-sur-Yvette, France.
Cell Biophys. 1988 Jan-Jun;12:105-17. doi: 10.1007/BF02918353.
Here is presented a short survey of the main aspects of the involvement of nucleotide hydrolysis in the polymerization of actin and microtubules: 1) XTP hydrolysis is not tightly coupled to the polymerization process; XTP hydrolysis and phosphate release generate an unstable XDP-polymer which is maintained at steady state, in the presence of XTP, by terminal XTP-subunits; this feature can generate patterns of phase transitions of the polymer between stable and unstable conformations; 2) Interactions between subunits are involved in the mechanism of XTP hydrolysis; 3) XTP cleavage on the polymer is followed by the slow release of Pi; the structural and thermodynamic characteristics of the transient XDP-Pi-polymer may play a crucial role in the regulation of the dynamics of microtubules and actin filaments.
1）XTP水解与聚合过程并非紧密偶联；XTP水解和磷酸释放产生不稳定的XDP-聚合物，在XTP存在下，由末端XTP亚基维持其稳态；此特征可产生聚合物在稳定和不稳定构象之间的相变模式；2）亚基间相互作用参与XTP水解机制；3）聚合物上的XTP裂解后，Pi缓慢释放；瞬时XDP-Pi-聚合物的结构和热力学特性可能在微管和肌动蛋白丝动力学调节中起关键作用。
