Yingrong Han

The Catalytic Mechanism Based on a Four-State Model of F1-ATPase

F1-ATPase, a rotary motor enzyme, can catalyse ATP hydrolysis in which the central γ-subunit ratates inside the α3β3 cylinder. Here, a four-state catalytic model of F1-ATPase is studied in which we think that the ATP hydrolysis and synthesis are ATP-dependent and ADP/Pi-dependent, respectively. The results show that the catalytic ratation mechanism of F1-ATPase is affected distinctly by the ATP/ADP/Pi concentrations. The model accords well with the expermental observations. Moreover, when the external load exists, the mean rotation rate of F1-ATPase is also affected apparently, and the external torque which decreases the mean ratation rate of the F1 motor to zero equals to the constant one which is produced during the ratation of the motor.

A Dynamical Model on the Network of p53-Mdm2 Feedback Loop Regulated by p14/19ARF

Base on new experimental results, we give a dynamical model to study the dynamical mechanism of the negative feedback loop composed of p53 and Mdm2 proteins regulated by p14/19ARR The oscillatory behaviors for the activities of p53 and Mdm2 proteins regulated by p14/19ARF in individual of cells are described in our dynamical model. The results help us build a basal network about oscillatory behaviors among p53, Mdm2 and P14/19ARR The dynamical model and its numerical results will help us understand the oscillatory behavior among other network of different proteins.

Research of the ATPase’s rotation catalysis stochastic transition dynamics

In this paper, based on the structure of the ATPase and the master equation, we put forward a stochastic hopping model which describes the rotary four-state motor’s dynamics action. Finally, we obtained the relationship of the angle velocity ω, diffusion coefficient and the ATP’s concentration, and got a result which accords with the rotary motor’s biological mechanism.

Dynamical model of P53-Mdm2-P14/19ARF network to radiation in population of cells

From the recent experiments of γ radiation and models given before, we study the dynamical model of p53 and Mdm2 regulated by p14/19ARF in population of cells. In order to study how they infect the mechanism of the negative feedback loop, we give numerical results to study the oscillatory features of p53, Mdm2 and p14/19ARF in population of cells. The dynamical model and results will help us understand the oscillatory features of p53, Mdm2 and p14/19ARF to radiation in population of cells.

Researching on the Selectivity Permeability Mechanism of K Channels Based on a Hierarchical Model

Potassium channels are membrane proteins that allow the passage of potassium ions at near diffusion rates while severely limiting the flux of the slightly smaller sodium ions. Based on the three dimensional structure of KcsA with a D- alanine at position 77 (KcsAD-Ala77), the authors use a hierarchical model of K channel selectivity permeability process involving ab initio quantum calculations and Brownian dynamics. The results showed that the mutated K channel, KcsAD-Ala77, lost its ability of discriminating the sodium ions from the potassium ions which is consistent with the experimental data. Our results indicate that interactions between permeant ions and the selectivity filter can influence ion selectivity.