| Summary: | 碩士 === 輔仁大學 === 化學系 === 107 === Phosphofructokinase-1 (PFK-1) is a tetramer allosteric enzyme that has effector site to bind effector in regulation of the enzyme conformation and active site activity. This enzyme is well known to be involved the mutation which has been linked to cancer development. Basically, PFK-1 enzyme catalyzes the phosphorylation of fructose-6-phosphate (F6P) and ATP to fructose-1,6-bisphosphate (F-1,6-bP) and ADP as a rate-limiting step of glycolysis. We report here the characterization of water dynamics of PFK-1 enzyme in plant respiration in which, it is clarified experimentally, that water molecules play a crucial role and that the temperature dependence of the respiration rate shows non-Arrhenius behavior. We find by the molecular dynamic simulation that these PFK-1 channels provide water-microsolvation environment in restriction of hydrogen bonding-network and drive the allosteric interaction between the active and effector sites. In addition, careful analysis led us to propose a new reaction mechanism with PFK-1 which is associated with the rearrangement of the hydrogen-bond network and the magnesium ion coordinates with water molecules, asparagine and phosphate oxygenated. As a result, PFK-1 acts as a smart mechano-chemical system by regulating the protein cavities enclosing the channel and interface for the trapped water motion and networking the communication between different sites. The temperature dependence of the microsolvated water diffusion of PFK-1 enzyme calculated by the present microscopic MD simulation has shown a good agreement with the non-Arrhenius behavior obtained by the experiment, thus unraveling how water-microsolvation channels controls respiration with water.
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